can anyone help me with providing an explanation for each of the correct answers

Question

Subject-verb agreement A
1a. Did you know a famous animal-rights activist has criticized horseracing because of the dangers involved? 1b. Did you know a famous animal-rights activist have criticized horseracing because of the dangers involved
Subject-verb agreement B
2a. Peer editing academic papers require critical-thinking skills and diplomacy.
2b. Peer editing academic papers requires critical-thinking skills and diplomacy.
Subject-verb agreement A
3a. Vitamins that are sold in a health-food store are not regulated by the Food and Drug Administration.
3b. Vitamins that are sold in a health-food store is not regulated by the Food and Drug Administration.
Using regular and irregular verbs A
4a. John has become a rather good actor.
4b. John has became a rather good actor.
Using regular and irregular verbs A
5a. Some athletes have taken drug tests to prove they are not on steroids.
5b. Some athletes have took drug tests to prove they are not on steroids.
Using regular and irregular verbs B
6a. I lay my book on the table, but now I cannot find it.
6b. I laid my book on the table, but now I cannot find it.
Using the correct form of be and have in the present tense B
7a. I was interested in working on the presidential campaign if the opportunity still exists.
7b. I am interested in working on the presidential campaign if the opportunity still exists.
Verb form and verb tense B
8a. Since American Idol premiered on television, many talented contestants have appeared on the show.
8b. Since American Idol premiered on television, many talented contestants appeared on the show.
Verb form and verb tense A
9a. The ancient Egyptians built pyramids as burial sites for their leaders.
9b. The ancient Egyptians have built pyramids as burial sites for their leaders.
Identifying antecedents A
10a. The antecedent in the following sentence is students: Students in online classes have to be organized to keep up with their assignments.
10b. The antecedent in the following sentence is class: Students in online classes have to be organized to keep up with their assignments.
Identifying antecedents B

Answer 1

These explanations should get you started.

1. The subject (activist) is singular and needs a singular verb (has criticized).

4. The helping verb "has" needs the past participle "become."

10. The students (plural) is the antecedent of the pronoun (their).