Question

Rainforests make up only 3 percent of the earth's surface. Over half the world's plant, animal, and insect species live there.
Combine the above sentence with a conjunction that expresses a contrast:

• A. Rainforests make up only 3 percent of the earth's surface, so over half the world's plant, animal, and insect species live there.
• B. Rainforests make up only 3 percent of the earth's surface, therefore over half the world's plant, animal, and insect species live there.
• C. Rainforests make up only 3 percent of the earth's surface and over half the world's plant, animal, and insect species live there.
• D. Although rainforests make up only 3 percent of the earth's surface, over half the world's plant, animal, and insect species live there.

Answer 1

The correct option is D Although rainforests make up only 3 percent of the earth's surface, over half the world's plant, animal, and insect species live there.

We can determine the correct answer with the help of logic and by eliminating the incorrect answer.

The subordinating conjunctions used to express contrast in a sentence are though, although, as, however, whoever, whatever and notwithstanding.

And, so do not express contrast. We can thus eliminate options A and C as incorrect answers.

Option D is the correct answer as the conjunction 'although' joins the two sentence to express a contrast.

Option B is incorrect as the conjunction 'therefore' is used to explain cause and effect.