Ryan Hart tracked the orbit of dozens of stars in the center of our galaxy to find
out that they were all moving REALLY fast
around a central object that was dark and
very massive. What was at the center of
their orbit?
A microscopic black hole

Another condensed' galaxy

A super massive black hole

A vacuum of space that causes matter to
behave differently

Which features on mars point to the possibility of liquid water on the planet? impact craters with sharp rims volcanic cones with craters gullies and stream-like channels mountain ranges with faults

Sally turns on her cellular telephone to speak to her friend who is located thousands of miles away. which of the following best describes how such a telephone is able to transmit and receive information? a. the cellular telephone transmits, receives, and encodes information using only sound waves. b. the cellular telephone transmits, receives, and encodes information using only electromagnetic waves. c. the cellular telephone transmits information by electromagnetic waves to a receiver which then encodes them and produces sound. d. the cellular telephone transmits information by sound waves to a receiver which then encodes them and produces electromagnetic waves.

Are good conductors of heat also good conductors of electricity? explain your answer.