Final answer:
In the sentence, 'the ball is red,' the word 'red' is an adjective that serves as a feature of the ball, describing its color. Words may have static forms but their functions can change based on the sentence structure, like 'eating' functioning as a noun in certain contexts.
Step-by-step explanation:
In the sentence “the ball is red,” red is a feature of the ball. When we describe the ball as red, we are attributing a characteristic or property to it, which is its color. In this context, 'red' operates as an adjective because it is giving us more information about the noun 'ball' by describing its appearance. Forms and Functions in Sentences. It is important to understand that in grammar, words can have different forms and functions. The form of a word is static; it refers to its categorization as a noun, verb, adjective, and so on. However, the function of a word is about how it is used within a sentence, and it can change depending on the sentence structure. For instance, the word 'eating' in the sentence "Eating an apple a day can keep the doctor away" functions nominally (as a noun) because it is the subject of the sentence, despite its formal definition as a verb.