Which word functions as an adjective in the sentence: "The teacher praised the diligent students."

The word that functions as an adjective in the sentence "The teacher praised the diligent students" is "diligent". Here's the step by step explanation:

1. Identify the subject of the sentence: In this case, the subject is "The teacher".

2. Identify the verb of the sentence: In this case, the verb is "praised".

3. Identify the object of the sentence: In this case, the object is "the diligent students".

4. Look at the words that are describing or modifying the object: In this case, "diligent" is the word that is modifying "students".

So, "diligent" is the adjective in this sentence because it is describing the quality of the students.