What is one of the largest impact basin in the Solar System?
a. Crisium Basin
b. Caloris Basin
c. Imbrium Basin
d. Mare Tranquillitatis
e. Aitken Basin
Question 2
A planetary nebula is visible due to ____.
a. blackbody continuum radiation from the interstellar medium
b. line emission from the interstellar medium
c. scattering from dust grains ejected by a dying star
d. blackbody continuum radiation from a hot gas ejected by a dying star
e. line emission from ionized hydrogen gas ejected by a dying star