Environmental system

2. One of the first Demographers.
4. American environmentalist who warned of the dangers of overpopulation.
7. Marin biologist who put in march the modern ambiental consciousness.
8. Notable figure in science and therapeutic medisin.
10. Discover the cure and create Inmunity to Viruela.
11. The first African American woman to recieve the Nobel prize.
13. Link the water contaminated because of a bomb that cause the outbreak of cholera in Londres.
16. Published more than 300 articles about nature.
17. One of the first conservation thinkers.
19. America's first environmentalist.
20. A day where people collect garbage, plant trees, sign petitions.

1. Get the independence of India.
3. Danish economist focused on the development of agriculture and its relation to population growth.
5. Evolution Homosapiens.
6. Implement ational parks and national forests in the United States.
9. Leader of the movement "New thinking".
12. Nobel prize winner for his micro-credits system.
14. Scientist, meteorologist, writer famous for the Gaia hypothesis.
15. The great increase in production of food grains and better management techniques.
18. Published "Walden" and "Civil disobedience".