I have a few astronomy questions for a study guide

I have a really long Astronomy study guide but some of the questions I can't find in the book or notes. I was hoping there would be someone who could help.

1. Which of th efollowing is not cited as justifying the search for life beyond our solar system?
a. exoplanets orbiting nearby stars
b. disks of gas and dust around young stars in the Orion Nebula
c. the production of carbon, nitrogen, and oxygen by most stars
d. liquid water in interstellar clouds

2. Observtional evidence suggests that galaxies formed relatively ____ in the history of the Universe from objects that were ____ than galaxies.
a. early... smaller
b. late... smaller
c. early... larger
d. late... larger

3. Which list of starship engine types in order of increasing energy yield per kilogram of propellant?
a. antimatter, fission, fusion
b. fusion, fission, antimatter
c. fission, antimatter, fusion
d. fission, fusion, antimatter

4. Which of the following National Enquirer headlines represents an imposibility? (Inquiring minds want to know!)
a. Astronaut seen to retain youthfulness as he nears black hole!
b. visitor to black hole appears to become slimmer when approaching destination
c. black hole tourist return after visiting singularity - photos on page 3!
d. We spent our honeymoon above the event horizon of LMC X-3!

5. The___ stars have the longest main-sequence lifetimes
a. largest-diameter
b. bluest
c. greenest
d. lowest-mass

6. The thick, warm gas and dust clouds around a newly forming star will emit large amounts of ___ radiation, even though the star itself may not be clarly visible.
a. optical
b. X-ray
c. ultraviolet
d. infrared

7. Which of the following is true about parallel lines in a positively curved Universe?
a. they would intersect somewhere
b. their separation would be uniform
c. their separation could vary with location, but never equal zero