Which of the following describes a gerund and how it functions in a sentence?

Question

1. A gerund is a noun that functions as the subject of a sentence.
2. A gerund is a verb ending in -ing that functions as a noun in a sentence
3. A gerund is a verb ending in -ing that functions as a verb in a sentence
4. A gerund is a noun that functions as the direct object receiving the action in a sentence

Answer 1

2. A gerund is a verb ending in -ing that functions as a noun in a sentence.