SCIENCE 12.docx

Republic of the Philippines
Department of
Education
REGION X – NORTHERN MINDANAO
SCHOOLS DIVISION OF BUKIDNON
SCIENCE SHS MOCK TEST QUESTIONS
1. You are standing on a scale in an elevator. You notice that your weight is
decreasing.
What can you conclude? The elevator is_ .
A. Accelerating upward
B. Moving at constant acceleration upward
C. Accelerating downward
D. Moving at constant acceleration downward
2. If the force of gravity on balloon is 3,000N, and the lift force provided by the
atmosphere is 2,900N, in which direction is the net force acting?
A. Upward
B. towards the east
C. Downward
D. there is no net force
3. If a horse pulls on a calesa at rest, the calesa pulls back equally as much on the
horse. Will the calesa be set into motion?
A. No, because the forces cancel each other.
B. Yes, because there is a net force acting on the calesa.
C. Yes, because there is a time delay between action and reaction.
D. Yes, because the horse’s pull on the calesa is larger than the calesa’s pull on
the horse.
4. Which of the following statements is not one of Newton’s Laws on motion?
A. In the absence of an unbalanced force, an object moves at constant velocity
B. For any force there is always an equal but opposite reaction force.
C. The force and the acceleration of a body are towards the same direction.
D. What goes up must come down.

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5. Two cars are following a 35 ton tractor-trailer truck traveling down the highway at a
high rate of speed. One of the following vehicles is significantly heavier than the
other. Wind coming off the back of the truck shakes them both. One of them does not
sway as much as the other. Which one does not sway as much as the other?
A. The lighter car will sway more than the heavier car.
B. The heavier car will sway more than the lighter car.
C. A only
D. A and B
6. When an object is placed in front of a plane mirror the image is:
A. Upright, magnified and real
B. Upright, the same size and virtual
C. Inverted, demagnified and real
D. Inverted, magnified and virtual
E. Upright, magnified and virtual
7. A narrow beam of light is incident on the surface of a plane mirror. The initial angle
between the incident ray and reflected ray is 2α. If the mirror is turned around point
A by the angle Θ what is the change of the angle between two rays?
(A) Θ (B) 2Θ (C) 4Θ (D) Θ/2 (E) Θ/4

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8. A candle is placed in front of a concave mirror. The image produced by the mirror
is:
A. Real, inverted and magnified
B. Real, inverted and demagnified
C. Virtual, upright and magnified
D. Virtual, upright and demagnified
E. Real, upright and magnified

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9. A very narrow light ray AB strikes the surface of a concave mirror as shown on the
diagram. Which of the following diagrams represents the reflected ray?
10. Which of the following are the postulates of special relativity?
I. The color of light is the same for all frames of reference.
II. The speed of light is the same for all frames of reference.
III. The relative speed of objects is the same for all observes in moving frames of
reference.
A. I and II
B. I and III
C. II and III
D. II and IV
A.
D.
B.
E.
B.

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11. One of two identical twins is an astronaut, while the other is areal estate broker. The
astronaut embarks on high speed space travel and is gone for several years. Upon the
astronaut’s return, the two twins reunite and observed their physical appearances. The
observation will be that .
A. Both have aged the same
B. The astronaut has aged less
C. The astronaut more
D. The real estate broker has aged less
12. The following physical quantities are classified as the fundamental quantities of
measure: time, length, and mass. The mass of the body is believed to be constant
wherever it is taken and we consider it also the same whether the body is in motion or at
rest. However, Einstein considers the mass of a moving body not constant. Why is this
so can be understood by the law of acceleration. Recall that acceleration depends not
only on force but also on the mass of the object as well. Einstein believed that when work
is done on the object to increase its velocity, its mass increases as well. So, the force
produces less and less acceleration as velocity increases. The relationship between mass
and velocity is given in the following equation:
m = the mass of the body when it is in motion,
Mo = mass of the body when it is at rest
What is the mass of the electron traveling at half the speed of light? (Mass of an electron
at rest is 9.11 x 10-31 kg.)
A. 1.05 𝑥 10 -30 𝑘g
B. 2.05 𝑥 10 -30 𝑘g
C. 1.05 𝑥 10 -29 𝑘g
D. 2.05 𝑥 10 -29 𝑘g
13. In the special theory of relativity, it is important to know the velocity of an object relative
to an observer. It plays a very important role in attaining the effects of time dilation, length
contraction, relativistic momentum, and energy-mass transformation. If we are to
determine the velocity of an object relative to that of an observer, oftentimes we have to
add two or more velocities together in an equation. According to the special theory of

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elativity, the velocities are related according to the velocity-addition equation:
u = the velocity of the object as measured by an observer on Earth,
u’ = the velocity of the object as measured by an observer in the moving frame which
itself is moving at a velocity, v, relative to Earth.
A car is approaching an observer on Earth with a velocity v = 0.85c. A person in
the car throws a ball towards the observer at a velocity of u’ = 0.60c relative to the car. At
what velocity does the observer on Earth see the ball approaching?
A. 0.196𝑐 B. 0.916𝑐 C. 0.96𝑐 D. 0.916𝑐
14. Microwaves were invented during World War II when radar technology was being
developed. In the last 40 years, the microwave oven has become a ubiquitous
appliance. Microwave technology enables us to thaw and cook food much more rapidly
than conventional appliances do. The cooking action in a microwave oven results from
the interaction between the electric the field component of the radiation with the polar
molecules—mostly water—in food. All molecules rotate at room temperature. If the
frequency of the radiation and that of the molecular rotation are equal, energy can be
transferred from the microwave to the polar molecule. As a result, the molecule will
rotate faster. This is what happens in a gas. In the condensed state (for example, in
food), a molecule cannot execute the free rotation. Nevertheless, it still experiences a
torque (a force that causes rotation) that tends to align its dipole moment with the
oscillating field of the microwave. Consequently, there is friction between the
molecules, which appears as heat in the food. (Source).
Which of the following statements best describe why microwaves heat food so quickly?
A. The radiation is absorbed by nonpolar molecules that created friction and will
generate heat in food.
B. The radiation is absorbed by polar molecules and can, therefore, reach different
parts of food at the same time.
C. The polar molecules in foods when exposed to radiation will heat and cooks the
food.
D. The nonpolar molecules in foods when exposed to radiation will heat and cooks
the food.
15. Read the following information and answer the question below.

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Which of the following statements is correct about food containers that are
utilized and safe for microwaves?
A. They do not contain polar molecules and are therefore not affected by
microwaves.
B. They contain polar molecules and are therefore affected by microwaves.
C. They do not contain nonpolar molecules and are therefore not affected by
microwaves.
D. They contain nonpolar molecules and are therefore affected by microwaves.
16. A student heated a beaker of cold water (on a tripod) with an alcohol lamp. When
the gas is ignited, the student noticed that there was water condensed on the
outside of the beaker. Which of the statements best described the observation?
A. The gases from the environment react with the heat from the alcohol lamp and
condense.
B. The gases from the alcohol lamp condense on the outside of the cold beaker.

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C. The water from the container seeps into the wall of the beaker.
D. When methane burns in the air, it forms carbon dioxide and water vapor. The
water vapor condenses on the outside of the cold beaker.
17. Suppose you are hiking in one of the mountains of Bukidnon. Upon reaching your
destined area, you decide to hard-boil an egg and eat it to help regain your strength
following the strenuous work. To your surprise, the water seems to boil more quickly
than usual, but after 10 min in boiling water, the egg is still not cooked. Due to a
decrease in atmospheric pressure, it takes less energy to bring the water to its boiling
point. Hence due to less energy needed, the water boils at a lower temperature. The
summit of the mountain is 9,511 ft above sea level. At this altitude, the atmospheric
pressure is only about 0.7 atm.
Figure 1 below shows how pressure affects the melting point and boiling point of
water.
Figure 1. This phase diagram tells us that increasing the pressure on ice lowers its
melting point and that increasing the pressure of liquid water raises its boiling point.
Which of the following statements best described your observation?
A. The amount of heat delivered is inversely proportional to the temperature of the
water, so it takes a longer time to hard boil the eggs.
B. Because water boils at a lower temperature at high altitudes, hard-cooked eggs
will take longer to prepare.
C. At higher altitudes, the air pressure is higher, so the boiling point of water
decreases thus needing more time in cooking eggs.
D. At higher elevations, the higher atmospheric pressure means heated water
reaches its boiling point more quickly.

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For numbers 18 -19, read the following section of an article about the DNA Fingerprinting
In 1985 a British chemist named Alec Jeffreys suggested that minisatellite
sequences provide a means of identification, much like fingerprints. DNA fingerprinting
has since gained prominence with law enforcement officials to identify crime suspects.
To make a DNA fingerprint, a chemist needs a sample of any tissue, such as blood
or semen; even hair and saliva contain DNA. The DNA is extracted from cell nuclei and
cut into fragments by the addition of so-called restriction enzymes. These fragments,
which are negatively charged, are separated by an electric field in gel. The smaller
fragments move faster than larger ones, so they eventually separate into bands. The
bands of DNA fragments are transferred from the gel to a plastic membrane, and their
position is thereby fixed. Then a DNA probe—a DNA fragment that has been tagged with
a radioactive label—is added. The probe binds to the fragments that have a
complementary DNA sequence. An X-ray film is laid directly over the plastic sheet, and
bands appear on the exposed film in the positions corresponding to the fragments
recognized by the probe. About four different probes are needed to obtain a profile that
is unique to just one individual.
The first U.S. case in which a person was convicted of a crime with the help of
DNA fingerprints was tried in 1987. Today, DNA fingerprinting has become an
indispensable tool of law enforcement.
Source: Chang, Raymond, Overby, Jason. (2022). Chemistry Fourteenth Edition. New York:
McGraw-Hill (adapted)
18. The following statements explain how DNA profiling (fingerprinting) can be used
to identify people by their unique genetic code EXCEPT.
A. identify suspects whose DNA may match evidence left at crime scenes
B. clear persons wrongly accused of crimes
C. identify fathers in paternity cases
D. identify unknown remains using ashes.
19. Which of the following is the correct order for obtaining a DNA fingerprint?
I. X-ray fil detects radioactive patterns. These patterns are then compared to the
original sample.
II.DNA is extracted from the blood sample, then the restriction enzymes cut DNA
into fragments
III. Fragments are separated by gel electrophoresis and the band pattern is
transferred to a nylon membrane
IV. Radioactive DNA probe binds to specific DNA sequences
A. III, II, I, IV B. I, III, IV, II C. II, III, IV, I D. IV, I, III, II

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For numbers 20-21, refer to the statement below:
Experimental measurement of the rate leads to the rate law for the reaction, which
expresses the rate in terms of the rate constant and the concentrations of the reactants.
The dependence of rate on concentrations gives the order of a reaction. A reaction can
be described as zero order if the rate does not depend on the concentration of the
reactant, or first order if it depends on the reactant raised to the first power. Higher orders
and fractional orders are also known. An important characteristic of reaction rates is the
time required for the concentration of a reactant to decrease to half of its initial
concentration, called the half-life. For first-order reactions, the half-life is independent of
the initial concentration. (For first-order reactions, the half-life is independent of the initial
concentration).
The reaction X ⟶ Y shown here follows first-order kinetics. Initially different
amounts of X molecules are placed in three equal-volume containers at the same
temperature.
20. What are the relative rates of the reaction in these three containers?
A. The relative rates for (i), (ii), and (iii) are 1:2:3
B. The relative rates for (i), (ii), and (iii) are 4:3:6
C. The relative rates for (i), (ii), and (iii) are 6:3:4
D. The relative rates for (i), (ii), and (iii) are 2:4:6
21. How would the relative rates be affected if the volume of each container were
doubled?
A. The relative rates would be unaffected, but each of the absolute rates would
decrease by 50%.
B. The relative rates would be affected, and each of the absolute rates would
increase by 50%.
C. Both the relative and absolute rates would decrease by 50%.
D. Both the relative and absolute rates would be unaffected.
22. What are the relative half-lives of the reactions in (i) to (iii)?
A. The relative half-lives are 1:1:1.
B. The relative half-lives are 1:2:3.
C. The relative half-lives are 4:3:6.
D. The relative half-lives are 6:3:4.

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For numbers 23-24, read the following information and answer the question below:
A bombardier beetle discharging a chemical spray.
Maria Eisner
Source: Chang, Raymond, Overby, Jason. (2022). Chemistry
Fourteenth Edition. New York: McGraw-Hill (adapted)
23. Which of the statements regarding enzymes is true?
A. Enzymes cannot be used for a specific reaction.
B. Enzymes provide activation energy for reactions.
C. Enzymes are proteins that function as catalysts.
D. Enzyme activity cannot be regulated.
24. Which of the following best describes the role of a catalyst in a chemical
reaction?
A. A substance that is being used during a chemical reaction.
B. Catalysts increase the activation energy of a chemical reaction.
C. A catalyst decreases the speed of a reaction and lowers product yield.
D. A substance that speeds up a chemical reaction without being used up.
The bombardier beetle has a pair of glands
at the tip of its abdomen. Each gland
consists of two compartments. The inner
compartment contains an aqueous solution
of hydroquinone and hydrogen peroxide,
and the outer compartment holds a mixture
of enzymes. When threatened, the beetle
squeezes some fluid from the inner
compartment into the outer compartment.
The catalysts speed up the reaction, the
beetle is rapidly subjected to a spray of
painful, boiling chemicals.

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For numbers 25-26, refer to the paragraph below:
To make bread dough, a cook mixes flour, water, salt and yeast. After mixing, the
dough is placed in a container for several hours to allow the process of fermentation to
take place. During fermentation, a chemical change occurs in the dough: the yeast (a
single-celled fungus) helps to transform the starch and sugars in the flour into carbon
dioxide and alcohol. A few hours after mixing the dough, the cook weighs the dough and
observes that its weight has decreased. The weight of the dough is the same at the start
of each of the four experiments shown below.
25. Which two experiments should the cook compared to test if the yeast is the
cause of the loss of weight?
A. The cook should compare experiments 1 and 2.
B. The cook should compare experiments 1 and 3.
C. The cook should compare experiments 2 and 4.
D. The cook should compare experiments 3 and 4.
26. The bread consumed will be degraded, or broken down, in our bodies to provide
energy for growth and function. A general overall equation for this very complex
process represents the degradation of glucose (C6H12O6) to carbon dioxide (CO2)
and water (H2O):
If 500.0 g of C6H12O6 is consumed by a person over a certain period, what is the
mass (in gram, g) of CO2 and H2O produced? ( 6C12.01
1H1.01
8O16.0
)
The chemical reaction is C6H12O6 + O2 CO2 + H2O
A. 311.2 g CO2 and 650.0 g H2O C. 732.8 g CO2 and 300.0 g H2O
B. 150.0 g CO2 and 903.4 g H2O D. 545.20 g CO2 and 447.0 g H2O

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*For numbers 27-30, refer to the paragraph below.
Four boxes contain different organisms. Box A has organism with a waxy cuticle
to protect it against water loss. Box B contains organism with Xylem and Phloem. Inside
Box C is an organism with connective tissues like cartilage, blood, bone, and adipose.
Box D has organism with unspecified tissues. Its tendons are covered with Xylem and
phloem while its hairs are attached directly to its bones with no epithelial tissues at all.
27. Which of the following boxes contains an animal?
A. Box B B. Box C C. Box A D. Box D
28. Which of the following boxes contains organism that is NOT a plant?
A. Box C B. Box B C. Box E D. Box A
29. Which of the following tissue can also be found in Box A and B?
A. Muscular Tissue C. Neural Tissue
B. Vascular Tissue D. Epithelial Tissue
30. Which of the following boxes contains neither animals nor plants and is considered
unidentified species?
A. Box D B. Box C C. Box A D. Box B
31. An unidentified flying object (UFO) has cells with a typical nucleus with a nuclear
envelope, where its DNA lies inside it and is commonly linear. It does not have
mesosomes yet contains golgi apparatus. Which of the following statements best
describes this UFO?
A. The UFO is a prokaryote. C. It definitely possesses a eukaryotic
cell.
B. It is a kind of bacteria. D. It is probably an alien with indistinct feature.

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*For numbers 32-33, refer to the paragraph below:
Plants and animals may reproduce either sexually or asexually. In both cases, this
is the reason why species survived for thousands of years. Just like any other vertebrates
for example, human reproduce sexually by the joint of a sperm cell and egg cell to form
embryo. On the other hand, some organisms like bacteria and sponges reproduce having
no gametes involved. Yet, there are also exceptional cases that some organisms may
reproduce like for example those honey bees and even earthworms are called
hermaphrodites. However, unlike animals, reproduction in plants specifically in
Gumamela is unique and is termed double fertilization.
32. Which of the following scenario is TRUE?
A. Honey bees are some of the viviparous organisms.
B. Earthworms have both male and female reproductive organs.
C. Sponges give birth through live placental birth.
D. Bacteria are some of the oviparous organisms.
33. Why is fertilization in Gumamela plants termed as double fertilization?
A. Only those complete flowers may have double fertilization.
B. All plants both have male and female parts.
C. Only those perfect flowers can have double fertilization.
D. Since there are two sperm cells involved in the fertilization of
egg cell and two polar bodies.
*For numbers 34-35, refer to the paragraph below.
Thirdy’s botanical garden seemed to amuse the locals of Bukidnon. However,
there are times that his plants are attacked by some pathogens thereby becoming
vulnerable. One of them is the mayana particularly its leaves. Luckily, there are some
plants that can resist diseases. Unlike its neighbor plants, the entire kalabo plant, gabon-
gabon, asunting, and lagundi are resistant to infection. Sometimes, there are also
herbivores that roam around which created mess inside the botanical garden. Thirdy
noticed that these herbivores seemed to have eaten specific plants while refusing some.

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34. Which of the following immune responses do kalabo plant, gabon-gabon, asunting,
and lagundi possess?
A. Basal response
B. Hypersensitive response
C. Systemic acquired immunity
D. Jasmonic acid/ethylene pathway
35. What kind of immune response do some plants have for them not to be eaten by the
herbivores?
A. Basal response
B. Jasmonic acid/ethylene pathway
C. Systemic acquired immunity
D. Hypersensitive response
36. Kingdom Animalia shares a common characteristic with all its organisms. They have
several organ systems performing together for a common function yet a portion of it differs
from one species to another. Just like their firm framework which gives physical support
and protection for the body and provides surfaces for the attachment of muscles.
Earthworms have liquid support of their bodies. Corals, mollusks, crabs, and insects are
being protected with rigid external covering and it also serves as a defensive armor for
certain animals like turtles, crabs, and armadillos. Fishes, frogs, chickens, and other
vertebrates including humans have a hard framework inside their bodies. Some of the
muscles which attached to these skeletons are voluntary and can be control by thinking
like muscles of our arms and legs. Others are involuntary which means they work
automatically and without voluntary control; it move food along the digestive system and
allows the heart to pump and never stop working. How do crabs differ from chickens?
A. Crabs have exoskeleton while chickens have hydrostatic skeleton.
B. Crabs have endoskeleton while chickens have exoskeleton.
C. Crabs have exoskeleton while chickens have endoskeleton.
D. Crabs have endoskeleton while chickens have hydrostatic skeleton.
37. Which of the following factors are NOT homeostatically regulated?
A. Your father’s body temperature is 40ᴼC.
B. Your sister’s oxygen concentration is 100 mmHg.
C. Your mother’s blood pressure is 160/70.
D. The concentration of your carbon dioxide is 40 mmHg.

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38. Earth, the largest spaceship we lived in, has a very dramatic history. As we all
know, this is the only planet in our solar system that can sustain life ever discovered. Yet,
it started with the “chaotic eon”. Earth’s surface was continually bombarded by meteorites
and the very hot mantle caused severe volcanism. Earth would look very inhospitable.
As time passed by, Earth was probably warm and the atmosphere contained
mostly methane and little to no oxygen. Most of it was covered with ocean and continent
formation began.
Until then, it was experiencing the longest period that lasted almost half of its age. It was
the time of great changes: oxygenation of the atmosphere, origin and diversification of
eukaryote life, appearance of multicellular animal life, and the motion of continental drift.
After which, many fossils were found in layers of sedimentary rocks. Marine
invertebrate probably lived near the shores of shallow water. Fossils of trilobites and
brachiopods were found preserved in rocks. Amphibians came out of the sea and land
plants also began to develop during this period. Giant ferns and marsh plants provided
food to land animals which increased in number. Marine life also developed. Clams and
snails also increased in number. Fish became more abundant and showed a greater
variety of forms.
It passed an era which saw the formation of several continents. The large creatures
that existed were the dinosaurs. North and South America, Australia, Africa, and India
became separate plates. Reptiles were the first true terrestrial vertebrates existed which
flourished. However, many reptile groups became extinct.
Mountains were uplifted and new life forms started appearing after quite sometime.
Volcanic activity was also widespread, forming immense flows of lava and basalt. Warm-
blooded animals, such as marsupials like kangaroo, and primitive mammals, roamed the
land. And from this point in time, humans left their marks on land.
Based on the passage, which of the following conclusions is correct?
era.
A. Humans existed during the latter part which is called Cenozoic
B. Marine invertebrate probably lived near the shores of shallow water during
Mesozoic era.
C. Dinosaurs lived on Earth during Paleozoic era.
D. During Cenozoic era, the formation of several continents happened.

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39. Why do Earth has magnetic field?
A. It is because Earth is one of the Inner Terrestrial or Rocky-Icy Planets.
B. Because Earth has a complex terrain–ice mountains and vast crater free plains.
C. It is the because of the Earth’s solid metallic inner core and a
liquid metallic outer core.
D. Since Earth is a habitable planet.
*For numbers 40- 43, refer to the paragraph below.
Petrologists Vinxcent and Xiah are strolling while visiting to their grandpa’s place.
Along the way, they are fun of collecting peculiar rocks. Two of the rocks from Vinxcent’s
hand are solidified lava he called basalt and rhyolite while Xiah picked solidified magma
she named granite and gabbro. Not too distant from their grandpa’s house is a river
where they collected quite number of rocks formed from weathering, erosion, compaction
and cementation of sediments in which some of those rocks has fossil remains of leaves
and fishes. They were so amazed by the gigantic foliated and non-foliated rocks formed
because of heat and pressure/stress around their grandpa’s paradisiacal park.
40. Which of the following rocks are examples from Vinxcent’s hand?
A. Intrusive Igneous Rocks C. Extrusive Igneous Rocks
B. Sedimentary Rocks D. Metamorphic Rocks
41. Which of the following classification of rocks best describes the rocks they found
near the river?
A. Intrusive Igneous Rocks C. Metamorphic Rocks
B. Extrusive Igneous Rocks D. Sedimentary Rocks
42. Which of the following are the rocks picked by Xiah herself along their way while
strolling their grandpa’s place?
A. Extrusive Igneous Rocks C. Intrusive Igneous Rocks
B. Non-foliated Rocks D. Bioclastics
43. Which of the following is the rock found in paradisiacal park of their grandpa?
A. Clastic Sedimentary Rock C. Organic Sedimentary Rock
B. Metamorphic Rock D. Igneous Rock

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*For numbers 44- 45, refer to the paragraph below.
The Grand Canyon is located in a desert in the USA. It is a very large and deep
canyon containing many layers of rock. Sometime in the past, movements in the Earth’s
crust lifted these layers up. The Grand Canyon is now 1.6 km deep in parts. The Colorado
River runs through the bottom of the canyon. Several different layers of rock can be seen
in the walls of the canyon.
44. The temperature in the Grand Canyon ranges from below 0ᴼC to over 40ᴼC. Although
it is a desert area, cracks in the rocks sometimes contain water. How do these
temperature changes and the water in rock cracks help to speed up the breakdown of
rocks?
A. Freezing water dissolves warm rocks.
B. Water cements rocks together.
C. Ice smoothes the surface of rocks.
D. Freezing water expands in the rock cracks.
45. There are many fossils of marine animals, such as clams, fish and corals, in the
Limestone A layer of the Grand Canyon. What happened millions of years ago that
explains why such fossils are found there?
A. In ancient times, people brought seafood to the area from the ocean.
B. Oceans were once much rougher and sea life washed inland on giant waves.
C. An ocean covered this area at that time and then receded later.
D. Some sea animals once lived on land before migrating to the sea.
46. Limestones when exposed to a carbonic acid produced by the reaction of water and
carbon dioxide may causes weathering is a best example of
A. Oxidation B. Hydrolysis C. Erosion D. Carbonation

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47. The following scenarios best describe biological activities which helped in the physical
disintegration of rocks or at near earth’s surface, EXCEPT
A. Ants, rats, and earthworms break down rocks through burrowing.
B. Miners in search of gold ores in Surigao del Norte.
C. Plant roots can penetrate soil and break down rocks.
D. Oxygen and water reacts with iron-rich minerals producing a
reddish-orange color.
48. What must NOT be done during Earthquake?
A. You must go under the table to protect you from falling objects.
B. You must go in the open field away from the tall buildings or trees.
C. You must go near the sea to unwind.
D. None of the above
*For numbers 49-50, kindly refer to the figure below.
The figure above shows how water supplied to houses in cities is made fit for drinking.

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49. It is important to have a source of good drinking water. Water found underground is
referred to as ground water. Which of the following reasons best explain why there is less
bacteria and particle pollution in ground water than in water from surface sources such
as lakes and rivers?
A. When water goes down through the ground it will be strained by
rocks and sand, and so it has been naturally filtered compared to
lakes and rivers which are polluted by people and animals.
B. Because ground water passes through a filter and chlorine is added.
C. The ground water passes through a filter that cleans it absolutely.
D. Because it is not stirred and therefore don’t bring mud from the bottom.
50. Suppose that the scientists involved in the testing of water at the water plant discover
that there are some dangerous bacteria in the water after the cleaning process is
completed. What should people at home do with this water before drinking it?
A. Mix the water with chloride in a bucket and then drink it.
B. Boil the water.
C. Use a coffee filter to purify it again.
D. Buy bottled water until the cleaning process is fixed.
Prepared by:
NORMAN C. APLISE
Pangantucan National High School
JEANALYN A. CELIS
Old Damulog NHS
EMILIE A. FRANJE
Bukidnon National School of Home Industries
MARIA BETTY M. APARECIO LAMBAN
Quezon National High School

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