I did my graduate studies in human gross anatomy. Why did I pick such an icky "gross" subject? I love working in 1-on-1 and in small groups helping students learn hard stuff, and gross anatomy is pretty hard.
"Hard stuff" varies from person to person. Actually I tutor more maths and physical sciences now - math, calculus, physics, chemistry. It all stems from something you knew really well 1-2 years ago, but just don't "get" what your teacher or professor is talking about now.
We (you and I) develop what you need to know from what you DO KNOW right now. We figure out where most students go wrong, what is usually on exams, and how to succeed.
It's a partnership. I can't force-feed you I can only help you to eat what's on your plate, if you are willing to invest the time.