Progesterone. Print | Email article to a friend | Last updated: January 14, 2015. Progesterone is a hormone released by the corpus luteum in the ovary. It plays important roles in the menstrual cycle and in maintaining the early stages of pregnancy. It may also be involved in the growth of certain cancers.
Maple helicopters fall before the leaves drop from the trees. Maple trees (Acer spp.) produce winged seeds called double samaras, which twirl to the ground in late summer or early fall. They resemble helicopters in motion, earning them the common name of helicopters or whirligigs.
Quick Answer. The life span of a red maple tree is between 100 and 300 years. The average life span of a sugar maple tree is 300 years, although sugar maples can live up to 400 years. Silver maple trees typically live between 100 and 125 years. Continue Reading.