Explain why a person with a leaking heart valve has difficulty exercising

When some valve diseases get severe, exercise may be a problem, particularly for aortic valve disease. But for mild or "normal" valve leakiness, there is no reason to limit your exercise. Your valves will need to be repaired if you develop symptoms or the size or shape of your heart changes.

No because the eaeht is on a 23.5 degree axis tilt and so when it is winter the northern hemisphere is pointing away from the sun and the soutubern hemisphere is pointing toward the sun