HURRY!! Calisthenics are A. Exercise that can be done with little or no equipment. B. Exercises that calculate your physical fitness level. C. Lifestyle behaviors that increase your fitness level. D. Any exercises that have become health habits.

As you sit in the library with your friend studying for your weekly quiz on the integumentary system, you come upon an article about the hazards of prolonged exposure to the sun's rays. your curious nature leads you to research the subject further. you're fascinated to learn that minimal exposure to the sun allows you skin to manufacture vitamin d, which is important to maintain homeostasis. you also read that although sunscreen can protect you from the ultraviolet (uv) rays of the sun, some medications can actually increase a person's sensitivity to the sunlight.