Which biome do you think is most important? why?

I think the mountainous biomes are important, because they provide water during the summer when the ice caps melt.

There is no real answer to that question. The reason being is that they are all important to a species. They all have a vital role in the ecosystem and the life live in that area. For example, the tundra is home to animals that other places cant be found, like the polar bear.  In the Rain Forrest biome, it is home to tropical birds such as the toucans and poison dart frogs.
The last example is the taiga. The biomes supports life for bears, mountain lions and other wild animals such as the moose.
All of the biomes play a role in the survival of a species, and others do the same.

The answer to your question is that there is no biome that is more important or less important because they all play a role is the survival of life.

Idon't know how to do this but maybe ask your mom or dad