1. Yes, they expect to know the source of the funds, especially large amounts deposited into your account or transactions that show cash deposits. If they are not satisfied with source of funds explanation then visa could be rejected. Do they want to know the source even if I'm from a country liste...

I'm applying for a Tier 4 Visa to study a semester next year. My concern is that in the past, about 5 years ago, in 2015, i tried to apply for a visa to the U.S. and Canada and both got denied, but then, next year I decided to go to London (I don't need entry clearance to just visit the UK) to study...