What recommendation specifies the point at which a nutrient is likely to become toxic?

Groups of organisms with low biotic potential, such as gray whales, that produce at most one offspring every other year a) are r-selected b) are k-selected c) are not subject to density-dependent limiting factors d) show the initial stages of the extinction process e) have escaped from the processes of natural selection and adaptation

Cells destroy body cells infected by a virus or bacteria.

Which organelle breaks down sugar molecules that supply energy to the cell ?