<span>I think that it is:
Stay in the south during autumn and winter, and migrate to northern locations in the spring and summer.</span>
60 years is three half life for the substance, so 40*1/2^3=5
The body system that directly provides for this demand is the circulatory system. When you exercise, the circulatory and muscle system cooperate, in order to meet the increased needs for strength and energy. The circulatory system involves the network which delivers blood to every part of your body. This flowing of blood ensures that the tissues are oxygenated and rich in necessary nutrients. During exercise, more blood flows to and from your muscles, in order to deliver the necessary amounts of oxygen to complete the aerobic respiration.
Don’t mind me getting my free points
1. Atmosphere
2.terrestial biosphere
3. Ocean
