Sts

Across

2. roman
4. overcons
5. 19
7. speciesdiversity
10. overpopu
13. greek
14. sumer
15. catchdown
16. gendivers
17. growth
18. pollut
19. billion
20. chinese

Down

1. Aristotle
3. global
6. deforest
8. costarica
9. egypt
11. years
12. babylo