The Sun is composed entirely of oxygen and helium.

True
False

(for astronomy)

Plss anybody know how to do this? ? i need the answers from a through d

Which is not a source of noise pollution? a)airplanes b)acid rain c)machines d)cars

An ideal spring has a spring constant (force constant) of 2500 n/m, is stretched 4.0 cm, how much elastic potential energy does it possess? (a) 3j (b) 0.00j (c) 1j (d) 2j (e) 4j