Answer 1

Nope. It's intended to help you learn in an active way, rather than passive. When we learn passively, we lose most of the information that we've obtained, and I believe it's as much as like 70-80% within a couple weeks based upon studies. So practicing, tests, and engaging into what you're learning is all ways to help you receive and keep the information you've learned.

As well, SoloLearn is intended for beginners, so the goal is to help them learn the concepts while helping them progress forward. If you throw out the hardest questions to someone that's just now learning, you may put them off from programming or cause them to shy away because of the difficulty or frustration of not knowing the answers when you're learning.

However, a good solution would be having an entire area/section that's dedicated to practicing/exercises. Then you could have beginner to advanced exercises that anyone can do whenever they want to learn further. This would accommodate all sets of people.