These are not hypothetical questions. They are the fundamental basis for how to answer the OP's questions.
You have approximately 120 hours of waking time each week. Assuming that you are a full time student, you have class and are studying each week somewhere in the neighborhood of 40 hours/week. What do you do with the other 80 hours/week? You need to eat, you need to shower, you need to maintain relationships, you need to have fun, you need to do XYZ hobbies etc. When I look at someone's application and look at their ECs, I am trying to answer the question: who is this person when they aren't studying? How do you fill that 80 hours? Nobody is looking for the next mother Teresa. We just want to know if you spend 10% of those 80 hours goofing off, or 90% or somewhere in between. Some people have to work to pay for school or support families, some people play Division 1 sports, some people are concert pianists. It is understandable that the time they can commit to other things outside of school is going to be extremely limited. No adcom is expecting that you will spend every waking second doing enrichment activities. It is all about that spectrum.
If you don't have anything to put down. Don't put anything down.
Yoinked a little bit from one of my previous posts: http://forums.studentdoctor.net/threads/i-have-never-volunteered.1092556/#post-15583164