2.71 know the excretory products of the lungs, kidneys and skin (organs of excretion)

Organ	Mainly excretes	Explanation
lungs	carbon dioxide	the lung will excrete carbon dioxide as a waste product of aerobic respiration during exhalation
kidneys	excess water, salts, urea	the kidney will excrete excess water, salts and urea by ultralfiltration
skin	excess water and salts	the skin will excrete excess water and salts through sweat glands on skin by producing sweat