During the menstrual cycle, the main source of progesterone is

How have high taxes on tobacco products impacted the number of people who use them? a. the number of tobacco users has increased. b. the number of tobacco users has decreased. c. the number of tobacco users has not changed. d. the number of adolescent tobacco users decreased, while the number of adult users increased

Which kind of worm has a closed circulatory system? a planarian b fluke c pinworm d an earthworm

In which part of the body is a ball-and-socket joint found?