Chum salmon (oncorhynchus keta) are born in freshwater environments and then migrate to the sea near the end of their lives, they return to the freshwater stream where they were born to spawn. in freshwater, water constantly diffuses into the body and ions are lost from the body. in salt water, body water diffuses out of the body and excess ions are gained from the water. a salmon's gills have special cells to pump salt in or out of the body to maintain homeostasis. in response to the salmon's moves between freshwater and salt water, some cells in the gills are produced and others are destroyed. these changes made in the cells of the gills during the lifetime of an individual salmon are an example of ?
a) evolution.
b) trade-off.
c) acclimatization.
d) adaptation.
e) luck.

Acclimatization

Explanation:

Acclimatization refers to any modifications or alteration in physiological, behavioral or other processes in response to seasonal changes or temporary changes. Organisms make adjustments to survive under seasonal or temporary changes. These adjustments are called acclimatization.

In the given example, Chum salmon adjusts itself to the changed concentration of salts in fresh and seawater by production and destruction of specific cells. The cells serving as pumps to maintain the normal salt concentration of the body are formed when the salmon migrate to the marine environment near the end of their lives. As they return to the freshwater, the salt pumps are not required and therefore, the related cells are destroyed.

answer: c

explanation:

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.