Question

just like humans, blue whales need energy to live and grow. whales get the molecules they need to release energy from the air they breathe and the food they eat. blue whales eat krill, a type of tiny animal that looks similar to a shrimp. krill are high in fat and protein. to get enough food to maintain such large bodies, blue whales eat thousands of pounds of krill a day. the blue whale does not have teeth; instead, it has a part in its mouth that acts like a filter to keep the krill in and spit water out. the swallowed krill pass through the whale’s digestive system. in the stomach, acids and enzymes begin to break them down. this partially digested food is then broken down into amino acids and molecules from fats, which are absorbed in the small intestine.

Explanation:

The text describes the energy acquisition and digestive process of blue whales, including how they obtain food (krill), their feeding mechanism, and the breakdown of food in the digestive system. This relates to the study of living organisms and their biological processes, so the subfield of Biology (under Natural Science) is the most appropriate.

Answer:

Biology (under Natural Science)