Answer:
Her cats, which she adopted from a shelter, are fun to play with.
Explanation:
The correct subject-verb agreement emphasizes the use of the correct singular or plural tense with the given subject.
In the first sentence the subject is plural but the verb is singular.
My library <u>books</u>, which I borrowed last week, <u>is</u> overdue.
This is wrong.
The second sentences talks about two people one of them is the other's teammate but the teammate practices with him. The word practice should be used instead of practices . This is also wrong. There are two people and singular must be used.
<u>Salif and Peter</u>, his teammate, <u>practices</u> before and after school.
The third sentence again has singular subject and plural verb . This is again wrong. We are talking about the specific tree which is hundred years old.
The<u> tree</u>, which was one of the tallest redwoods, <u>were </u>hundreds of years old.
The last sentence is correct . There are many cats and they are fun to play with.
<u>Her cats</u>, which she adopted from a shelter,<u> are</u> fun to play with.