Question

some organisms can seem very odd if you look closely at how their body systems work! all organisms need to take in molecules from their environment. however, different organisms may have very different ways of taking those molecules in and getting them where they need to go. for example, in order to take in enough oxygen to supply its huge body during long dives, a blue whale’s lungs are almost 5,000 times larger than yours. grasshoppers don’t have lungs at all—they take in oxygen from the air through tiny holes along the sides of their bodies! trout and other fish use gills instead of lungs, and they take in oxygen directly from the water they live in. sea sponges and water bears have even stranger body systems. to learn more about amazing body systems, read one or more of the chapters that follow.

Explanation:

The text discusses how different organisms (blue whale, grasshopper, trout, sea sponges, water bears) have various ways to take in molecules (like oxygen) from their environment, focusing on their body systems. This relates to the study of living organisms and their biological processes, so the subfield of Biology (under Natural Science) is the best fit.

Answer:

Biology (under Natural Science)