Answer:
Remains of living organisms
Explanation:
Secondary consumers get their nitrogen and phosphorus from the remains (decayed bodies) of living organisms.
When plants and animals die and decay, microorganisms feed on their dead bodies, the activities of microorganisms (such as bacteria) on the remains of living organisms leads to the production of nitrogen and phosphorus for secondary consumers.
Therefore, the source of nitrogen and phosphorus for secondary producers is the remains of living things(e.g plants and animals).
