Which of the following statements is true of reflection nebulae?
A) They have a distinctive blue color.
B) The gases in reflection nebulae are excited to emit photons.
C) The spectrum of a reflection nebula is not the reflected absorption spectrum of starlight.
D) They are produced when a hot star excites the gas to produce an emission spectrum.
Question 2
_____ is a series of three nuclear reactions that builds a helium nucleus by adding protons one at a time.
A) The proton-neutron chain
B) The helium proton chain
C) The proton-proton chain
D) The hydrogen-helium chain