All of the following sentences are complex except

a) even though acid rain can have damaging effects, few people know much about it.
b) acid rain has been studied as an environmental issue by the government since the 1970s.
c) since they erode statues and corrode steel structures, the chemicals in acid rain are harmful.
d) since the industrial revolution began, emissions of sulfur dioxide and nitrogen oxide have increased.

B) Acid rain has been studied as an environmental issue by the government since the 1970's.

Explanation: All of the following sentences are complex EXCEPT Acid rain has been studied as an environmental issue by the government since the 1970's. "As an environmental issue" is a prepositional phrase, which makes the sentence a simple sentence. All of the other sentences contain one independent clause and one dependent (or subordinate) clause.

d

explanation:

read this passage from the crisis. what rationale is paine using for going to war with great britain? my own line of reasoning is to myself as straight and clear as a ray of light. not all the treasures of the world, so far as i believe, could have induced me to support an offensive war, for i think it murder; but if a thief breaks into my house, burns and destroys my property, and kills or threatens to kill me, or those that are in it, and to "bind me in all cases whatsoever" to his absolute will, am i to suffer it? what signifies it to me, whether he who does it is a king or a common man; my countryman or not my countryman; whether it be done by an individual villain, or an army of them? if we reason to the root of things we shall find no difference; neither can any just cause be assigned why we should punish in the one case and pardon in the other.

it is waged war against an army of countrymen

it would lead to independence from britain

it would be an offensive war

it would be a defensive war