I have this sentence:
"Body can get used to medications"
What articles could there be before "body" and when and why?
What article is there if I want to state that in general?
"body" is a concrete noun in the singular, and singular concrete nouns cannot do without articles, except in idiomatic phrases like "body and soul".
Concrete nouns like "body" (the same applies to all individual organs, like "heart", "liver", "stomach", etc.) will usually take the definite article when used in a general sense:
Other concrete nouns can be expressed in a general sense by using the zero article with the noun in the plural:
Instead, abstract nouns can be generalized by using the zero article (with the noun obviously in the singular form):