Correct Answer: Shoal

Solution : The correct one-word substitute for the given group of words is the second option.

Explanation for each option:

1. "Herd" - A herd typically refers to a group of mammals, such as cattle or sheep, moving together.

2. "Shoal" - A shoal specifically refers to a group of fish swimming together. This is the correct one-word substitute for the given group of words.

3. "Flock" - A flock is commonly used to describe a group of birds, such as a flock of sheep.

4. "Mob" - A mob usually refers to a large and disorderly crowd of people, not fish.

   Recommended