Hello, I hope y'all help me answer this science question, I will mark brainlist to whoever answers it right

1. Hot air is less dense then cold air therefore it is lighter the cold air. Because the hot air is less dense it helps lift the balloon up and because cold air is more dense it is heavier and helps the balloon slowly drop the balloon.

To be honest I don't know what 2 is but hope this helps some!

6.4 cm (max) - 25 cm (min)