Answer:
The correct answer is "a radical formed by carbons".
Step-by-step explanation:
Carboxylic acids are a group of compounds characterized by a functional group called the carboxyl group. In a structural formula of a carboxylic acid, such as RCOOH, R symbolizes the existence of a radical formed by a certain amount of carbons attached to the functional group called the carboxyl group (COOH).
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