Hunger games

3. The force that attracts a body toward the center of the earth
5. A biological community of interacting organisms and their physical environment
6. A group of atoms bonded together, representing the smallest fundamental unit of a chemical compound
8. A giant cloud of dust and gas in space
12. The process used by plants to convert light energy into chemical energy
14. A system of government by the whole population or all the eligible members of a state
15. A plastid in green plant cells which contains chlorophyll and in which photosynthesis takes place
16. When the sun reaches its highest or lowest excursion in the sky, marking the longest or shortest day

1. Any of the world's main continuous expanses of land
2. The envelope of gases surrounding the earth or another planet
4. A rupture in the crust of a planetary-mass object that allows hot lava and volcanic ash to escape
7. The process by which different kinds of living organisms are thought to develop from earlier forms
9. The regions of the surface, atmosphere, and hydrosphere of the earth occupied by living organisms
10. A extensive group of islands
11. A figure of speech in which a word or phrase is applied to an object or action to which it is not literally applicable
13. The resistance that one surface or object encounters when moving over another