What are the waste products excreted when making atp by:
a) aerobic respiration
b) anerobic respiration and
c) fermentation

a) Carbon dioxide and water.

b) Waste product varies according to the electron acceptor used in the process. Some of the waste products are H2S, methane, succinate, etc.

c) Waste products varies according to the final electron acceptor. Some of the waste products are lactic acid, ethanol and CO2, and Propionic acid,  acetic acid,  CO2, and H2.

Explanation:

a) Aerobic respiration uses molecular oxygen as the terminal electron acceptor and forms carbon dioxide and water as waste products.  

b) Anaerobic respiration is exhibited when a terminal electron acceptor is any substance other than oxygen. Some of the commonly used terminal electron acceptors during anaerobic respiration are nitrate, sulfate, and CO2 which in turn give NO2-, hydrogen sulfide and methane as waste products respectively.  

c) Fermentation is the process that uses pyruvate or its derivatives as an electron acceptor and produces acids and alcohol as waste products. Some of the waste products are lactic acid, ethanol and CO2, acetic acid and CO2 and H2.