Read the following paragraphs and tell where the main idea is located.
A. Despite the hatred that most people feel toward cockroaches, they do help humans in several ways. For example, they are perfect experimental animals and are used for scientific research in the laboratory. Breeding them is easy, for they thrive under almost any conditions. In studies on nutrition and food, cockroaches are good subjects because they will eat any kind of food. They can be used to study heart disease, and cancer researchers work with roaches because they grow cancerous tumors like those that are found in humans.
So, where is the main idea?
1) in the first sentence
2) in the last sentence
3) in the middle of the paragraph
4) in two sentences of the paragraph
5) not stated in the paragraph directly (meaning it's implied- like you're just supposed to know)