21. 1. 1st photosynthetic unicellular
organisms to thrive on
Earth
2-4. Needs of plant to make its
own food.
5. (What do you call the zone)
Earth’s distance from the
Sun.
22. 6. Amount of time that it takes
to turn around once on its
axis.
7. Imaginary line about
which a body rotates.
8. Earth’s axis is tilted ___
degrees.