Final answer:
The liver is the organ most severely damaged by alcohol abuse, leading to diseases such as cirrhosis and liver failure which can also strain the kidneys.
Step-by-step explanation:
Among the options provided, the organ most severely damaged by alcohol abuse is c. liver. Chronic excessive consumption of alcohol can cause liver disease, since the liver is a crucial organ of the excretory system responsible for breaking down toxic substances in the blood. The liver's function includes transforming ammonia into urea, which the kidneys then filter and excrete. When the liver's ability to perform these tasks is compromised due to alcohol abuse, it can lead to serious conditions such as cirrhosis and liver failure, and also puts added strain on the kidneys, potentially causing kidney dysfunction.
Alcohol affects the liver more severely than the other organs listed, as its primary role in metabolizing alcohol exposes it directly to high levels of toxins from chronic abuse. Heavy drinking can also impact the kidneys, leading to kidney disease, but this often results from the prior detrimental effects on the liver.