Question

What we can do to help the endangered species?
what causes endangered species?

Answer 1

What we can do to help the endangered species?
A lot of things, first we can stop polluting, second stop destroying those animals habitats.
What causes endangered species?
http://library.thinkquest.org/5736/causes.htm
(I usually dislike giving links but I think this links covers almost everything you need.)

Answer 2

do not kill them then will stay alive longer and the animals will be happy