The correct answer is letter A: the circulatory system removes waste from the tissues by converting carbon dioxide-rich blood into oxygen-rich blood that can be circulated throughout the body to support its several functions. Without the lungs the human body will not be able to process converting blood cells into oxygen-rich cells in the body.
Because the oxygen produced in photosynthesis is used in respiration, and the carbon dioxide produced in respiration is used in photosynthesis.
its d . electron because it has a negative charge of however many there are that are circling the atom
