Food, Water and protection from the sun.
They basically do what humans do to survive. Like humans need to eat to survive and we also need to sleep to survive.
Yes, on many levels... The whole of the ecosystem is balanced on plants, animals and the environment as a whole... Be it temperature by region or vegetation or insects.... If you remove just one component, the rest collapse...
To survive
Beacause there are not enough resources in the ecosystem,organisim must struggle with one another to things they need to survive
Depends what environment it is in.
Orcas require an ocean to survive and could not live in a barren desert.
cause we do
Yes.
yes
you need to be able to climb trees
fish
coz it does