____________ 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.
Emperor penguins with their black and white plumage stand out against the snow and colonies
All objects in the image are distant galaxies – not stars
Part of the Hubble Ultra-Deep Field image showing a typical section of space containing galaxies int
Three active forms of vitamin A: all-trans-retinol, -retinal, and –retinoic acid
How many origins of replication are active?
Life cycle of Rhizopus stolonifer, a black bread mold