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.
The tiger, Panthera tigris, was historically found throughout much of Asia, but at low population de
Apparent and True Orbits of Alpha Centauri.
The Spectra of Stars with Different Surface Temperatures.
Population of Major Civilizations of Europe, Asia, and Africa, AD 1500
Population and Settlement
Typical bacterial population growth curve showing the initial lag phase