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.

Organisms are more likely to be more preserved in mud than sand because mud is moist and wet, while sand is very dry.

The answer is b because a,c,and d are opinons