A(n) ____ is a commonly accepted set of scientific ideas and assumptions.
a. theory
b. paradigm
c. hypothesis
d. natural law
e. model
Question 2Emission nebulae are also called ____ because they are composed of ionized hydrogen.
a. HI regions
b. HII regions
c. Bok globules
d. HeI regions
e. reflection nebulae
Question 3A(n) ____ is a small circle whose center is located on the circumference of another larger circle.
a. equant
b. deferent
c. retrograde loop
d. ellipse
e. epicycle
Question 4The ____ is the nuclear fusion of three helium nuclei to form a carbon nucleus.
a. proton-proton chain
b. Carbon-Nitrogen-Oxygen cycle (CNO cycle)
c. triple-alpha process
d. Coulomb barrier
e. infrared cirrus
Question 5The book De Revolutionibus Orbium Coelestium
a. describes how Galileo's observations and Kepler's calculations proved the Copernican theory.
b. describes the construction of Galileo's telescope and his observations.
c. is a dialog written to convince the general public of the merits of the Copernican theory.
d. first described the Copernican theory.
e. describes the Tychonian theory.