Question

add or remove commas, if necessary, until the sentence has correct punctuation. eugene krabs saw a humpback whale, and four dolphins swimming near his boat.

Explanation:

In the sentence "Eugene Krabs saw a humpback whale, and four dolphins swimming near his boat," the comma before "and" is incorrect. When "and" is used to connect two parts of a compound predicate (where the same subject performs two actions or has two descriptions), we don't use a comma before "and". Here, "saw" is the main verb, and "a humpback whale" and "four dolphins swimming near his boat" are objects of the verb "saw", so the comma before "and" should be removed.

Answer:

Eugene Krabs saw a humpback whale and four dolphins swimming near his boat.