A few questions on basic astronomy...?

[Ashley R]

75. globular clusters are used to measure:
A size of galaxy
B mass of galaxy

77. the motion of our galaxy is measured by analyzing:
A 21 cm wavelengths
B doppler shifts
C both of the above
D none of the above

79. outward force keeping a degenerate WD star from collapsing:
A degenerate gas pressure
B internal pressure from heat
C rapid spinning
D pressure from the outward flow of neutrinos

78. oldest objects in universe are:
B globular clusters D comets

70. thinnest part of the Milky Way is characterized by:
A old stars
B young stars
C dark matter

71. on a galactic scale, stars form:
A early in galaxy's life
B later in galaxy's life
C before the galaxy's themselves
D all at once, at the same time as the galaxies

48. proto stars heat up by:
B gravitational energy of falling material
D energy from magnetic fields