Explanation:
1] ADAPTATION : WE HAVE BEEN ADAPTING A DOG AS A PET.
2] BIODIVERSITY : BIODIVERSITY IS THE VARIABILITY AMONG LIVING ORGANISMS FROM ALL SOURCES INCLUDING TERRESTRIAL, MARINE, AND OTHER AQUATIC ANIMALS
3] ISOLATION : THE PROCESS OR FACT OF ISOLATING OR BEING ISOLATED
4] VARIATION : DIFFERENCE BETWEEN ORGANISMS OR PLANTS
SO, THIS IS YOUR ANSWER
Answer: phytoplankton
Explanation: shrimp and krill are primary consumers. Primary consumers rely on producers for food. Phytoplankton are producers.