All solid objects above 0 kelvin emit energy.
a. true
b. false

true

Explanation: The zero Kelvin is the point where there is no energy between the atoms of the solid object, so there will no radiation emited, which means that there is no energy emited.

This has a lot of sense, if the object has temperature equal to zero, is logical to think that it can not radiate energy in the form of heat (or in any form)

c) up is the direction the magnetic force is acting on the charge.

compass can be used day and night, cloudy or sunny