Polar bears are in danger of extinction in the future if globalwarming continues, as their habitat, Arctic sea ice, is shrinkingevery year, making it difficult for bears to have enough food tolast through the lengthening summers.With a population of nearly 25,000, the polar bear is not in dangerof extinction now.
Aerobic exercise stimulates the growth of new neurons, also known as neurogenesis through the release of brain-derived neurotopic factors. Endurance exercises release Irisin, a hormone linked to improved cognitive function, fat loss and overall health.
The four main types of physical activity are aerobic, muscle-strengthening, bone-strengthening, and stretching. Aerobic activity is the type that benefits your heart and lungs the most. Aerobic activity moves your large muscles, such as those in your arms and legs. Running, swimming, walking, bicycling, dancing, and doing jumping jacks are examples of aerobic activity. Aerobic activity also is called endurance activity.