If a family has two children, what are the possible combinations of genders?

Approximately what percentage of pregnancies result in twins or more?

If 50% of the population is assigned female at birth, and 50% assigned male, what's the approximate ratio?

How many chromosomes does a typical human sperm cell contain?

How many chromosomes does a typical human egg cell contain?

What's the probability of having a girl if the previous child was a boy?

If a medication is 99% effective at preventing pregnancy, what's the failure rate?

Which of the following is a factor in population growth?

If the population grows exponentially, what type of curve would be seen on the graph?

Which of the following best approximates the average gestation period for humans?