Question

which of these are ecosystems with the lowest primary productivity?
deserts and tundra
wetlands and tropical rainforests
estuaries and coral reefs

Explanation:

Deserts have limited water and tundra has cold - harsh conditions, both restricting plant growth and thus having low primary productivity. Wetlands, tropical rainforests, estuaries and coral reefs generally have high primary productivity due to favorable environmental factors for photosynthesis and growth.

Answer:

A. deserts and tundra