Answer:
The moon, sun, river, clouds, mountain, rain, water and so on.
I think if the whale population decreased the surface fish populations would decline due to reduced populations of algae. This can be simply explained by the fact that, if the whale population is decreased, it means that the nitrogen rich feces that is supply nutrients to the algae would also decrease and therefore decrease the population of the algae and as a result the population of of the surface fish would also decline.
Habitat is where it lives, and it's niche is what other organisms it interacts with,what it eats, basically its job in an environment . Think of habitat as the address of the organisms house and the niche kinda like the job it has.
