ANATOMY

Detailed explanation-1: -cellular respiration, the process by which organisms combine oxygen with foodstuff molecules, diverting the chemical energy in these substances into life-sustaining activities and discarding, as waste products, carbon dioxide and water.

Detailed explanation-2: -Lungs aside, the three major organs that eliminate waste and harmful substances are the liver, kidneys and colon.

Detailed explanation-3: -As most high schoolers learn, the lysosome carries out waste disposal and recycling. In a process known as autophagy (meaning “self-eating”), it takes in old cellular components and unneeded large molecules, such as proteins, nucleic acids and sugars, and digests them with the help of enzymes and acids.

Detailed explanation-4: -Summary. Ammonia is the waste produced by metabolism of nitrogen-containing compounds like proteins and nucleic acids. While aquatic animals can easily excrete ammonia into their watery surroundings, terrestrial animals have evolved special mechanisms to eliminate the toxic ammonia from their systems.