Can you please help, they are multiple choice

Blank liquids and gases exert a buoyant force on objects placed in them

Which lists the fundamental forces in order, from strongest to weakest? strong nuclear, weak nuclear, electromagnetic, gravitational strong nuclear, electromagnetic, weak nuclear, gravitational gravitational, weak nuclear, electromagnetic, strong nuclear electromagnetic, gravitational, strong nuclear, weak nuclear

Give one example to show that when substances are mixed, it may result in a chemical or a physical change depending on the conditions.