What do enzymes change to affect the chemical reactions that take place in living cells?

I’m doing some practice exam questions for biology, and i’m not sure how to do these 3 parts to the question.

Which best describes how the common cold spreads in the human body? a bacteria burst out of normal cells killing them b viruses replicate inside respiratory cells c bacteria inject dna into normal cells d viruses insert dna into bacteria

Which statement describes john tuzo wilson’s contribution to the theory of plate tectonics?