In your introduction, you have to clearly identifiy the experience you are about to relate?
Answer:
Environmental scientists look for solutions to protect the environment, while chemists develop new products.
Explanation:
The last two sentences use the conjunction while meaning <em>whereas</em>, i.e. indicating a contrast. So the purpose of sentences 3 and 4 is to contrast certain things about environmental scientists and chemists. However, the fourth sentence contrasts only <u>level of education</u> required for these jobs.
The third sentence refers to <u>actual</u> <u>work</u> that environmental scientists and chemists do. Therefore, this sentence most accurately describes a way in which the jobs of environmental scientists and chemists contrast.
He persuaded the animals by using words like miserable to pull on the animals heart strings and show that he was right.