1, and 2 are the answer and by one and 2 I mean the first 2 statements
The correct answer
Physical activity ensures that the body burns all the excess calories. Excess calories is normally converted into fat that is stored in the body causing obesity and heart diseases because some of these fats are stored in the blood vessels thus hindering blood circulation. This means that in such event where tats deposit in the blood vessels conditions such as heart ischemia arises therefere, lowering the health of the victim. in summary, physical activities increases wellness and fitness while lack of physical activity reduces one health.
Usually there is a big difference when it comes to the purpose of the medical research. For instance, with forensics, you are attempting to solve passed crimes with DNA found on scenes. However, with medical, you are using DNA to do things for the living, or to help people stay alive. This could range anywhere from organ donations to blood mutations.
I'm going to be a forensics major, so if you have any more questions, PM me!
Hope this helps! <3
Answer Viruses
I believe the answer is viruses because viruses destroy and attack cells. Also they invade bodies. Hope this was helpful :)