Which of these organisms is not an omnivore?
A herring
B shrimp
C blue whale
D killer whale

c Blue whale

Explanation:omnivore is

an animal or person that eats food of both plant and animal origin.

Blue Whale is a carnivorous animal that despite the fact that it doesn't have proper teeth, survives on a diet that is mainly comprised of krill and small crustaceans, along with the occasional small fish.

explanation:

the fossil record extends back to a dog-like ancestor some 55 million years ago, which gave rise to the first horse-like species 55 to 42 million years ago in the genus eohippus.

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.