The orbits of population I stars I. are confined to disk of the galaxy. II. are very elliptical. III. are nearly circular. IV. are randomly inclined to the disk of the galaxy.
a. I
b. IV
c. I & IV
d. II & IV
e. I & III
Question 2
Opacity is
a. the balance between the pressure and force of gravity inside a star.
b. the force that binds protons and neutrons together to form a nucleus.
c. the force that binds an electron to the nucleus in an atom.
d. a measure of the resistance to the flow of radiation (photons) through a gas.
e. the temperature and density at which a gas will undergo thermonuclear fusion.
Genetic drift and population size.
Pulsars are highly magnetized, rotating neutron stars that emit a beam of electromagnetic radiation.
A Circumstellar Disk of Matter
Post–Main-Sequence Evolution of Low-Mass Stars
This painting depicts New Orleans in 1803, when the city was acquired—along with much of the modern
Rural versus Urban Population, 1820–1860