How can I write these two groups into one sentence phrases of recognizing general and specific phrases?

I’m really not sure about these two exercises, can you help me a bit here and give me some good answers? These two problems are mostly based on main ideas about Recognizing General and Specific Phrases with these two exercises I’m dealing with is to read a group of three sentences, then write a phrase that best states the subject or general topic for the sentences. I know how to do it but I find some other exercises pretty hard.So here they are:

1. Scientist think that a more reasonably defined danger level would mean that only 50,000 homes have radon concentrations that pose a danger to occupants.
2.Scientist outside the EPA have concluded that the standards the EPA is using are too stringent.
3.The United States Enviromental Protection Agency (EPA) regards 5 million American homes as having unacceptable radon levels in the air.
General Topic?

Next exercise:

1. They resist accepting a warm pink body as a corpse from which organs can be “harvested”.
2.The Japanese don’t incorporate a mind-body split into their models of themselves; they locate personhood throughout the body rather than in the brain.
3. In Japan the concept of brain death is hotly contested, and organ transplants are rarely performed.
General topic?