Why has there has been little change in the average height in Western countries over the last few decades?  a. The population has become overweight or obese, which negatively affects height.  b....

Why has there has been little change in the average height in Western countries over the last few decades?

 a. The population has become overweight or obese, which negatively affects height.

 b. People in Western countries have been exposed to more diseases.

 c. People have reached the upper boundary of their reaction range for height.

 d. Evolutionary infl uences are causing all populations to decrease in height.