RE: Is the earth round or flat ? How do you know that its round ? who has proved it ?

this argument is wrong.

someone can say “hey di-hydrogen monoxide is lethal if inhaled but it’s in our water”

that’s stupid. di-hydrogen monoxide is water

you can’t just believe what you see and hear if you don’t know it’s a credible source for certain.

a better argument would be proving that the claim the earth is round is credible.