Please help!! Will mark brainliest

Which statement best describes a keystone species? o a. it has littlelmenetic variation. it has an extremely high population. 0 b. 0 c. it remains unaffected by all environmental changes. od. it has a strong influence on the ecosystem. 0 e. it's the first species to populate a new ecosystem.

Which is an example of a decomposer? a. bear b.algae c.grass d.bacteria d bacteria

Aboy jumps into a cold swimming pool and his body tempature goes down hus muscles ,blood vessels