What is the most appropriate unit of measure for distances within our solar system?

a. parsec
b. light-year
c. arcsecond
d. astronomical unit (au)

Arollercoaster car at the top of a hill has potential energy kinetic energy chemical energy light energy

Over the last 90 years, scientists have added to the body of evidence supporting the big bang theory. what is the latest piece of evidence discovered in 2014?

Which process does not require the presence of a physical substance in order to transfer heat? air in the atmosphere is heated by the ground. this warm air then rises, and cooler air falls. this is an example of what type of process? how is conduction different from radiation?