Chapter 12

4. The uppermost thinnest layer on Earth where all life exists.
6. Transfer of pollen grains from anthers to stigma of a flower.
7. Solid surface or land on Earth.
10. Reproduction that involves two individuals and individuals formed show variations.
11. Animals that lay eggs.
13. The hottest planet
17. Single cell formed after fertilisation.
18. A plant that propagates by buds on its leaves.
19. A layer of air surrounding the earth.
20. Fusion of male and female gametes to form a zygote.

1. Reproduction in which individuals formed are identical to the parent.
2. Planets farther off from the Sun, also called outer planets.trapped heat main
3. When solar radiations reflected back warm the Earth's surface.
5. The habitable zone where liquid water exist on the surface.
8. Structure formed after repeated divisions of a zygote.
9. Includes all water bodies on Earth.
12. Also called terrestrial planets.
14. Animals that give birth to young ones.
15. The habitable or life-sustaining part of Earth.
16. Special reproductive cells that carry half the genetic material.