Final answer:
The heritability of adult stature being 25 percent implies a moderate positive correlation between the heights of fathers and sons, indicating that taller fathers tend to have taller sons.
Step-by-step explanation:
The narrow-sense heritability of adult stature in people being 25 percent implies that 25 percent of the variability in adult height is due to genetic factors.
The correlation coefficient in adult height between father and son is a measure of the strength and direction of the linear relationship between their heights. In this case, a heritability of 25 percent suggests that the correlation coefficient between father and son heights would be approximately 0.5.
This means that there is a moderate positive correlation between the heights of fathers and sons, indicating that taller fathers tend to have taller sons, although other factors such as nutrition and environment also contribute to adult height.