Researchers classified pregnant women as being nondrinkers or light, moderate, or heavy drinkers; they examine the weights of their children at regular age intervals to see if alcohol during pregnancy results in poor growth. prospective observational study retrospective observational study survey experiment.

The answer is: prospective observational study.

Explanation:

A prospective observational study searches for outcomes of a particular situation, identified at the begining of the study. In this case, the variable identified was the alcohol consumption of pregnant women, which was identified and classified at the beginning. During the study, the children were watched during a long period, specifically their weight, to establish a relationship between the situation first identified (alcohol during pregnancy), and poor growth of the child.