What is an adjective?

An adjective is a word that describes a noun, providing additional information about its qualities, characteristics, or state. For example, in the phrase "blue sky," the adjective "blue" describes the noun "sky" by telling us the color of the sky. This descriptive function is essential in enriching language and providing clarity. Adjectives can answer questions like "What kind?" "How many?" or "Which one?" about the nouns they modify. This is why the answer regarding adjectives as words that describe nouns is correct.

Other options focus on different parts of speech: actions are linked to verbs, verbs can be modified by adverbs, and pronouns replace nouns. Each of those definitions pertains to parts of speech distinct from adjectives, reinforcing that the primary role of an adjective is indeed to describe nouns.