A 17 year old basketball player has collapsed on the court.

Did the universe cool off or get hotter as it expanded after the 'big bang"?

Which of the following always exist between two objects having mass ● elastic force ● contact force ●gravitational force ●magnetic force

Earth's atmosphere is unique among the planets and is able to support life because it contains a large amount of a) oxygen b) helium c) methane d) carbon dioxide