Question

(1) 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?

Answer 1

The sentence that is the paragraph's topic sentence is (1) Scientists generally agree that Earth is getting warmer due to what's called the greenhouse effect.
It encompasses everything said in the remaining sentences.

Answer 2

(1) Scientists generally agree that Earth is getting warmer due to what's called the greenhouse effect.

The first sentence outlines what the rest of the paragraph is about. In the paragraph, the author explains how greenhouses trap heat. He then uses this explanation to demonstrate how the Earth's atmosphere traps heat and raises the temperature on Earth.

When looking for the topic sentence, it is helpful to read the entire paragraph and then answer the question, what is the passage about? After answering the question in your own mind, then choose the best sentence that matches your summary.