Introduction:
In the given sentence, "Rani had a basket of fruits. They are mangoes," the noun is the word "basket". A noun is a word that represents a person, place, thing, or idea.

Explanation:
The sentence describes a situation where Rani possesses a basket of fruits. The noun in this sentence is "basket" as it is the main subject of the sentence and refers to a physical object.

Breakdown of the sentence:
Let's break down the sentence to analyze its components:
- "Rani" is a proper noun, representing a person's name.
- "had" is a verb, indicating possession or ownership.
- "a" is an indefinite article, representing a non-specific item.
- "basket" is the noun, representing a container.
- "of" is a preposition, indicating the relationship between "basket" and "fruits".
- "fruits" is a noun, representing multiple edible items that grow on trees or plants.
- "They" is a pronoun, referring to the plural form of the fruits mentioned earlier.
- "are" is a linking verb, connecting the subject ("They") with the noun ("mangoes").
- "mangoes" is a noun, representing a specific type of fruit.

Conclusion:
In the given sentence, the noun is "basket" as it is the main subject and refers to a physical object that Rani possesses.

Rani