Different environments cause different species to
a)become more diverse
b) become less diverse
c)become extinct
d)have similar traits

I think the best answer is become more diverse since different environments require different adaptations which will lead to further diversity.  I am interpreting the question as if you have different species all in different environments. 
I hope this helps and let me know if I interpreted the question incorrectly in the comments so that I can fix it.

Answer is: hydrogen is being oxidized.chemical reaction: co₂ + h₂ → co + h₂o.oxidation half reaction: h₂ → 2h⁺ + 2e⁻.reduction half reaction: c⁺⁴ + 2e⁻ → c⁺².oxidation is increase of oxidation number, hydrogen change oxidation number from neutral charge (in molecule of hydrogen) to oxidation number +1 (in water).