Spring tides occur
a. at new moon and first quarter moon.
b. at first quarter and third quarter moons.
c. at new moon and full moon.
d. at third quarter and full moons.
e. at noon and midnight.
Question 2In the proton-proton chain
a. no neutrinos are produced.
b. energy is released because a hydrogen nucleus has a greater mass than a helium nucleus.
c. no photons are produced.
d. carbon serves as a catalyst for the nuclear reaction.
e. energy is produced in the form of gamma rays and the velocity of the created nuclei.
Question 3Retrograde motion
a. is observable for planets located between Earth and the sun.
b. is observable for planets more distant from the Sun than is Earth.
c. is only observable for the moon.
d. is observable for all planets.
e. none of the above
Question 4____ is the thermonuclear fusion of hydrogen to form helium operating in the cores of massive stars on the main sequence.
a. The CNO cycle
b. The proton-proton chain
c. Hydrostatic equilibrium
d. The neutrino process
e. none of the above