Question

Blue whale, which inhabits Antarctica, has a requirement of more than a million calories per day. Which one of the following planktonic organisms forms the bulk of food to fulfill its caloric requirement?
A. Dinoflagellates
B. Diatoms
C. Green algae
D. Krill

Answer 1

Hint: According to a recent study on filter-feeding whales that highlights how crucial their eating habits may be for recycling nutrients in the water, the largest animals to have ever lived on Earth suck up significantly more food than scientists previously believed.

Complete step by step solution:
According to research published in Nature, baleen whales like blue, fin, minke, and humpback whales typically consume about three times more annually than previously thought. For instance, a blue whale in the eastern North Pacific might consume 10 to 20 tonnes of food per day.

That's somewhere between 20 and 50 million calories worth of food.

The biggest animal to ever exist is the blue whale. Ironically, it maintains its enormous size by consuming krill, some of the tiniest marine life. With its mouth wide at a straight angle and moving quickly, a foraging whale charges at a group of these shrimp-like creatures. Its mouth enlarges and its tongue, which is the size of an elephant, inverts to make more room as a result of being pushed back by the rushing water. Any krill present in the water is filtered out and ingested by the whale as it consumes up to 110 tonnes of water.

Therefore option D, Krill, is the correct answer.

Note: Although blue whales have a maximum weight of 180 tonnes, the majority of adults weigh between 72 and 135 tonnes.
African elephants, which range in weight from 2.5 to seven tonnes, are the biggest land mammals.
The blue whale is the heaviest mammal to have ever existed on Earth, exceeding even the greatest dinosaurs in size.