Which of the following body systems work together to remove the waste products of cellular respiration from cells.
a. the digestive and respiratory systems
b. the respiratory and circulatory systems
c. the digestive and circulatory systems
d. the circulatory and excretory systems

The answer is B. The respiratory system and circulatory system.

During cellular respiration, cells use oxygen to oxidize glucose. Oxidation of glucose releases energy and carbon dioxide. Carbon dioxide is a waste product.  It must be removed from cells. With help of circulatory system, carbon dioxide is transported through the blood from the cells to the lungs. Lungs are the part of respiratory system, from there carbon dioxide is expelled out via trachea and nostrils.  

a motor homunculus represents a map of brain areas dedicated to motor processing for different anatomical divisions of the body.

homunculus represents the importance of various parts of your body as seen by your brain. as a result, they take up a lot of brain space. although the cortical homunculus is a curiosity, penfield's work in mapping the brain's relationship to the body was invaluable.

answer: ice crystals in air

the water from the water body or another source of water gets evaporated as water vapor as an effect of heat on water. these water vapor rises in the upper layers of the earth atmosphere under high atmospheric pressure. the atmospheric pressure of these water molecules starts to decrease due to the effect of cold air. the invisible water vapor condenses into visible water droplets and ice crystals.these ice crystals and water droplets being less denser than the surrounding air floats on air as clouds.