A. they arose out of Africa less than 200,00 years ago
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.
Answer:
a. is converted to NAD+ by an enzyme called dehydrogenase
Explanation:
The electron transport chain of cellular respiration is the final step that oxidized NADH and FADH2. These reducing powers are formed during glycolysis and Kreb's cycle. Complex I of the electron transport chain present in the inner mitochondria membrane is NADH dehydrogenase. This protein complex accepts electrons from NADH and oxidizes it into NAD+. NADH dehydrogenase couples oxidation of NADH with the pumping of proton towards the intermembrane space.
The answer is tropical areas. The tropical areas obtain more
radiant energy from the Sun than they lose to space through terrestrial
radiation, and vice versa for polar areas. Earth has an energy remaining in the
tropics and an energy scarcity for the polar areas.
