Different characteristic of healthy community

What is an important step to prove something is valid or not? determining the reliability observing research testing

The part of the nephron provides initial filtering of the blood in the urinary system.

Which of the following is a true statement? a. the male sex hormone is called estrogen. b. the female sex hormone is called testosterone. c. both sexes manufacture some amount of the sex hormone associated with the opposite sex. d. only males secrete testosterone and only females secrete estrogen