In a food chain, a secondary consumer is typically an organism that eats primary consumers. In this case:
- a) Squid: Squid are considered secondary consumers as they often feed on smaller fish and crustaceans, which act as primary consumers.
- b) Anchovy: Anchovies are primarily plankton feeders and act more as primary consumers, eating diatoms and copepods.
- c) Diatom: Diatoms are algae, serving as primary producers, not consumers.
- d) Tuna: Tuna can vary in their position but are typically viewed as higher-level consumers, including secondary and tertiary roles depending on what they eat.
- e) Copepod: Copepods are small crustaceans and primarily consume phytoplankton, therefore they are also primary consumers.
Considering the options, the squid is a clear example of a secondary consumer, while both tuna and squid can fit the role depending on the context of the food chain. However, the best answer based on common classifications would be the squid.