1. Osteoporosis is a disease that primarily affects postmenopausal women, causing decreased bone density and brittle bones that are vulnerable to fracture. The hormone calcitonin is sometimes used to...

1. Osteoporosis is a disease that primarily affects postmenopausal women, causing decreased bone density and brittle bones that are vulnerable to fracture. The hormone calcitonin is sometimes used to treat osteoporosis. Why?

2. Only one sperm fertilizes an egg. If this is the case, why can low sperm count be a factor in infertility?