Research on pregnant women who were severely malnourished during famines during world war ii found that their children were, on average, unaffected physically or intellectually as adults.

That statement is true

This result can be used as proof that certain type of genotype among humans are not affected by environmental factors. (some of us are born to be physically stronger or intellectually inferior without making any effort, environmental factors could only resulted in very little deviation.)

i believe the answer is:   psychological  experiment

in this experiment, wilhelm wundt became the first person that implement scientific method in analyzing the pyschological phenomenon.

due to this result, wilhelm wundt also able to make psychology to be acknowledged as a separate scientific field from biology.