Question

Scientists generally agree that Earth is getting warmer due to what's called the greenhouse effect. (2) A greenhouse stays warm because sunlight and heat coming through the glass roof are mostly trapped. (3) The heat doesn't radiate back into the atmosphere because it's held in by the glass. (4) Something like that happens on Earth. (5) The atmosphere acts like a blanket that keeps the Sun's heat from leaking away into space.

Which sentence is the paragraph's topic sentence? 

       A. Sentence 1   B. Sentence 5   C. Sentence 2   D. Sentence 3

Answer 1

The correct answer here is sentence 1, so the correct answer is A. The first sentence 'Scientists generally agree that Earth is getting warmer due to what's called the greenhouse effect' is the topic sentence because it sets up what the rest of the text is going to discuss. The other options as answers to this question are all just supporting sentences for this first topic sentence.