Question

read the passage, then answer the question that follows.
scientists have studied the benefits of hobbies having a pastime reduces stress. it can improve mood, help memory, and strengthen friendships. relaxing hobbies such as knitting or bird - watching reduce cortisone, the stress hormone. some hobbies, such as sports and clubs, encourage friendships, and numerous studies have found a connection between relationships and happiness.
which revision best corrects the underlined sentence?
○ scientists have studied the benefits of hobbies. having a pastime reduces stress.
○ scientists have studied the benefits of hobbies, having a pastime reduces stress.
○ scientists have studied the benefits of hobbies, but having a pastime reduces stress.
○ scientists have studied the benefits of hobbies; however, having a pastime reduces stress.

Explanation:

The original underlined sentence is a run - on sentence. We need to separate the two independent clauses. The first option splits the two independent clauses into two separate sentences, which is a correct way to revise a run - on sentence. The second option uses a comma to separate two independent clauses, which is incorrect (a comma splice). The third and fourth options use "but" and "however" respectively, which imply a contrast, but there is no contrast between the two ideas (scientists studying benefits of hobbies and having a pastime reducing stress) — they are related, not contrasting.

Answer:

Scientists have studied the benefits of hobbies. Having a pastime reduces stress.