____________ galaxies contain a supermassive black hole at their centers while active nuclei are present in ____________of galaxies
a. Most; a few percent
b. Most; the majority
c. A small minority; a few percent
d. A small minority; the majority
Question 2
Star clusters are important to our study of stars because
a. all stars formed in star clusters.
b. the Sun was once a member of a globular cluster.
c. they give us a method to test the our theories and models of stellar evolution.
d. they are the only objects that contain Cepheid variables.
e. All of the other choices are correct.
Black River Brookie
Elk wintering in Jackson Hole, Wyoming after migrating there during the fall
The Black Bee-eater (Merops gularis) is a species of bird in the Meropidae family.
An “Intermediate-Mass” Black Hole
Communication as active process
Notice the small motor gear on the left drives a larger plastic gear (black), which then drives ...