Answer:
The distribution for the number of weeks pregnancy lasts for a mother is typically a unimodal distribution, with a single peak. The majority of pregnancies last around 38-42 weeks, with fewer pregnancies lasting shorter or longer than this period. This creates a bell-shaped curve, with the peak at the most common duration and a gradual decrease in frequency as the duration becomes shorter or longer than the mode.
However, it's worth noting that there can be some variations in this distribution based on different factors, such as the age of the mother, health status, and other demographic characteristics. For example, teenage pregnancies and pregnancies in older women may have slightly different distributions with different peaks due to biological and social factors. Nonetheless, a unimodal distribution is the most commonly observed distribution for the number of weeks pregnancy lasts for a mother.