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 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

Hint: Conjunctions are used to join clauses, phrases, and words together for constructing sentences. Conjunctions are used to make a link between words. For example: and, but, yet, nor and etc.

Complete step by step answer:
Notice how both sentences are very contrasting in nature. One sentence suggests that the forest cover is very less while the other highlights how rich the fauna is over there. Thus, we need to choose a conjunction that supports this conflict.
Option 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 – is an incorrect answer because this sentence does not show any contrast. Thus, this is an incorrect answer.
Option 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 – is an incorrect answer because in this sentence there is no contrast shown. However, the conjunction ‘therefore’ is used to explain cause and effect and there is no cause and effect being given. Thus, this is an incorrect answer.
Option 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 – is an incorrect answer because the subordinating conjunction do not express any contrast in a sentence. Thus, this is an incorrect answer.
Option 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 – is the correct answer because the conjunction that ‘although’ joins the two sentences to express a contrast. Thus, this is the correct answer.
In this particular question, subordinating conjunction is used. Subordinating conjunction always introduces a dependent clause, and dependent clause is a group of words that cannot stand alone as a complete sentence.

So, the correct answer is “Option D ”.

Note:
Here in this question subordinating conjunctions used to express contrast in a sentence are though, although, as, however, whoever, whatever and notwithstanding. Conjunctions have three types and they are: coordinating (and, but, for), correlative (not only, but also, either – or and etc.) and subordinating (although, unless, though, which, because etc.)