Correct Answer: Option 2 a feedback mechanism

It is a negative feedback mechanism. This is the special mechanism for turning the hormones off after they have done their job. When the blood sugar level drops, the amount of insulin produced also falls, and when blood sugar level has risen back to normal, the amount of adrenalin and glucocorticoids falls.

Correct Answer: Option 1 More oxygen is delivered to muscle cells

Various exercises require a predominance of certain muscle fiber utilization over another. Aerobic exercise involves long, low levels of exertion in which the muscles are used at well below their maximal contraction strength for long periods of time. Aerobic exercise, which rely primarily on the aerobic (with oxygen) system, use a higher percentage of Type I (or slow-twitch) muscle fibers, consume a mixture of fat, protein and carbohydrates for energy, consume large amounts of oxygen and produce little lactic acid.

Exercise has no direct effect on the rate of blood cell excretion, rate of digestion, and hormone production.