Which was least likely to have been a component of earth’s atmosphere before life began? a-sulfur b-carbon dioxide c-oxygen d-water vapor

According to social exchange theory, altruistic behaviors benefit the individual who performs them. t/f

The diagram shows a boulder rolling down a hill into a valley and then up the opposite hill. at which position does the boulder have the greatest kinetic energy? ab c d

Athird point charge q3 is now positioned halfway between q1 and q2. the net force on q2 now has a magnitude of f2,net = 5.861 n and points away from q1 and q3. what is the value (sign and magnitude) of the charge q3?