Which sentence includes a gerund?

1. I am running a marathon this weekend.
2. My family is impressed by my cooking
3. The runners are lacing up their shoes
4. A healthy breakfast of steaming hot biscuits is served

2. My family is impressed by my cooking

The sentence that includes a gerund is: "My family is impressed by my cooking."

A gerund is a form of a verb that functions as a noun and ends in -ing. It is created by adding -ing to the base form of the verb.

In order to determine which sentence includes a gerund, we need to look for a word that ends in -ing and is functioning as a noun.

Analyzing the sentences:

1. "I am running a marathon this weekend."
In this sentence, the word "running" is a verb and is not functioning as a noun.

2. "My family is impressed by my cooking."
In this sentence, the word "cooking" is a noun formed from the verb "cook" by adding -ing, and it is functioning as the object of the preposition "by." Therefore, this sentence includes a gerund.

3. "The runners are lacing up their shoes."
In this sentence, the word "lacing" is a verb and is not functioning as a noun.

4. "A healthy breakfast of steaming hot biscuits is served."
In this sentence, there is no word ending in -ing that is functioning as a noun.

Therefore, the sentence that includes a gerund is:
2. "My family is impressed by my cooking."