Answer:
Krill and orca are both consumers that depend on plankton for their energy. Krill are small, shrimp-like animals that are a major food source for many marine animals, including orcas. Orcas are large, apex predators that hunt in packs to catch krill and other small marine animals. Rabbits and seaweed are not consumers that depend on plankton for their energy. Rabbits are herbivores that eat plants, and seaweed is a plant that gets its energy from the sun.
Here is a table that shows the relationship between these consumers and plankton:
Consumer : Relationship to plankton
Krill: Plankton is a major food source
Orca: Plankton is a prey item
Rabbit: Plankton is not a food source
Seaweed: Plankton is not a food source