Why are the terms under fat and over fat uselful?

The average american baby will blank their birthweight by the time they turn one year-old

How is the central idea developed further? (a) the author elaborates on the treatments for allergies in adults and how they work. (b) the author quotes the reactions of experts and the methods used to conduct the study. (c) the author compares the different rates of food allergies shown in children and adults. (d) the author indicates the limitations of the study because of differences in health care.

Which term names the change in the environment that causes and or chasms to change its activity