1. If Earth was swapped with Mars, then the orbital
velocity of Earth is now...
a. larger
b. the same
c. smaller
2. For every solar mass in stars, there is typically ___
solar masses of gas and ___ solar masses of Dark matter present in
a galaxy cluster.
a. 5 and 50.
b. 0.5 and 5
c. 500 and 5000
d. 500,000 and 5 million.