Step-by-step explanation:
I am only sure about the first one but as for the rest I am not really but I tried...if you need explanations to the first one feel free to ask me
Answer:

Step-by-step explanation:

Best Regards!
Answer:
3,850
Step-by-step explanation:
have a good day!!
This is an A. <span>observational study. They are observing the use of cell phones differs between people with or without cancer.
Happy studying ^-^</span>