Someone please help will mark as brainliest

Why does his teacher ask him to balance the equation by including the correct coefficient

Which of the following observations indicates that there is a small, dense, positively charged part in the center of an atom? some uncharged particles are scattered by a gold foil. all uncharged particles are attracted towards a gold foil. all positively charged particles pass straight through a gold foil. some positively charged particles bounce back from a gold foil.

Why does a plastic bottle that is sealed at a high altitude change it’s shape when taken to lower altitude