ANSWER: A. Exercise is important for the body to function properly.
Exercise deliver adequate amounts of oxygen and remove waste from body tissues by regulating nervous, respiratory, circulatory and hormonal systems in the body. During exercise, body tissues and other metabolic processes in the body requires oxygen.Low levels of oxygen and higher levels of carbon dioxides are mainly detected by sympathetic division of the autonomic nervous system which control the physical activity of the body by increasing heart rate, blood pressure and respiration as a result of this there is an increase in the amount of blood pumped per minute by the heart and oxygenated body gets distributed to the tissues. This also involves release of glucose by the liver as an energy reservoir to control the level of blood glucose pancreas secrete insulin hormone , thyroid gland is also stimulated in response to increase heart rate.
Option B)
They prevent most of the Sun's rays from reaching Earth, thereby preventing Earth from heating up
Answer:
D. membrane-enclosed organelles
Explanation:
Natural selection. Only spiders that were more resistant to the pesticide lived through the first spraying of the pesticide, thus we're the only ones that could reproduce. This in turn made the offspring of the previous generation more resistant as well; thus making the pesticide less effective.