Micro-organisms are microscopic organisms that are either single-celled or multi-cellular. The study of microorganisms is called microbiology, which began with Antonie van Leeuwenhoek's discovery of microbes in 1675 using his own microscope. Bacteria constitute a large domain of prokaryotic micro-organisms, typically a few micrometers in length and found in a variety of shapes. Bacteria were some of the first life forms on Earth and are found in most habitats including soil, water, hot springs, radioactive waste, and deep within the Earth's crust, as well as in symbiotic and parasitic relationships with plants and animals.

1. Name-Devansh Bhandari
Std-V
Topic-micro-organisms

2. Micro-Organisms
• A microorganism is a microscopic
organism, which may be a single cell [1] or
multi cellular organism. The study of
microorganisms is called microbiology, a
subject that began with Antoine van
Leeuwenhoek 's discovery of
microorganisms in 1675, using a
microscope of his own design.

4. Bacteria
• Bacteria constitute a large domain of prokaryotic
domain of prokaryotic micro-organisms . Typically a
few micro -meters in length, bacteria have a number
of shapes, ranging from spheres to rods and spirals.
Bacteria were among the first life forms to appear on
Earth , and are present in most of its habitats .
Bacteria in habit soil, water, acidic hot springs,
radioactive waste[2] and the deep portions of Earth's
crust . Bacteria also live in symbiotic and
parasitic relationships with plants and animals. They
are also known to have flourished in manned
spacecraft.[3]