The theory that Mercury shrank slightly when it was young has been proposed to explain
a. extended lava plains.
b. large craters.
c. magnetic field.
d. lobate scarps.
e. regolith.
Question 2
Poor clusters
a. contain more than 1000 stars and are found in the halo of the galaxy.
b. contain lots of young stars and are found in the disk of a spiral galaxy.
c. contain more than 1000 galaxies and are generally elliptical in shape.
d. contain fewer than 1000 galaxies and tend to be irregularly shaped.
e. are found in the nucleus of the galaxy.