Bone mineral density (BMD) is a measure of bone strength. Studies show that BMD declines after age 45. The impact of exercise may increase BMD. a. True
b. False

As you age, your body may reabsorb calcium and phosphate from your bones instead of keeping these minerals in your bones. This makes your bones weaker. When this process reaches a certain stage, it is called osteoporosis. Many times, a person will fracture a bone before they even know they have bone loss.

Marine iguanas are herbivores. They dive into the cold ocean to find algae to eat. When the iguanas are not feeding, they rest on the lava rocks near the island shores to warm their bodies. Compared to land iguanas, marine iguanas have darker body coloring, flatter tails, shorter snouts, and longer, curved claws.