Great quiz! Since the questions are general knowledge, it's almost impossible to tell if it's plagiarised or not.
One area the quiz can improve on is the explanations. They were usually just the answer of the question itself. Being a little more descriptive wouldn't hurt.
Unfortunately, this test will not be able to receive a prize:
Not an original test. Questions, answers, explanations were copied from an existing test. E.g.:
#q1 https://www.examveda.com/which-is-the-hottest-planet-in-the-solar-system-82047/
#q3 https://quizizz.com/admin/quiz/5c6a57cbb07a4f001a9ddd4a/solar-system
#q4 https://books.google.ru/books?id=199UDwAAQBAJ&pg=PT99&lpg=PT99&dq=%22Which+is+the+coldest+planet+in+the+solar+system?%22&source=bl&ots=N8xcVyw94p&sig=ACfU3U2gdmV3hq0YkrjSgTo57H0NPmlvmg&hl=ru&sa=X&ved=2ahUKEwiSjZyi-5XqAhXCFXcKHVWhDqsQ6AEwEHoECAkQAQ#v=onepage&q=%22Which%20is%20the%20coldest%20planet%20in%20the%20solar%20system%3F%22&f=false
One area the quiz can improve on is the explanations. They were usually just the answer of the question itself. Being a little more descriptive wouldn't hurt.
Good luck on the contest :)