You could say that material forces would not exist if not for the ideas of people who brought these into existence. Thank you for posting your question. I hope this answer helped you. Let me know if you need more help.
I would say ...homework. Math...
Answer:
By Quantum physics.
Explanation:
Quantum physics is the theory in which time travel is possible means you can see your past but not your future. But changing in the past does not effect you up comming future.
BTW I Learned This From Avengers EndGame LOL
Answer:
if thats a test you have to do it yourself, sorry ^^
Explanation:
