What problems would you expect to observe in an ecosystem without primary consumers?

Primary consumers are taken away from the ecosystem, then there wouldn't be a way for the energy to go from producer level to a higher level of consumers which only eats primary consumers. Tertiary and higher order consumer population, the population increases in producers but decreases in secondary.

kelp are large brown algae that live in cool, relatively shallow waters close to the shore. they grow in dense groupings much like a forest on land. these underwater towers of kelp provide food and shelter for thousands of fish, invertebrates, and marine mammal species.

e) all of the above