Good for practice however in question challenge, on some questions if user selects just 1 correct answer out of 2 more correct one instead of “all of above” it marks it wrong and resets the challenge. This implies user needs to answer all multiple options on test, which think is not correct. Once you have practiced enough the goal is to practice with these challenges so user would be selecting correct answers fast & waste time reading all options to select all of above, making mistake which shouldn’t be a mistake on first place. They should allow both answers, any correct or all of above as acceptable and let users continue with challenge.
Also answers repeat after 100 so there is no difference, it should have different correct answer option in each set of 100, else it’s same answer again and again (challenge will be knowing all answer options)