_____ can link together to form proteins by joining ends and releasing water molecule.

_____ can link together to form proteins by joining ends and releasing water molecule.
 
  A) Lipid molecules
  B) Disaccharides
  C) Amino acids
  D) Polysaccharides

Question 2

In the Drake equation, Nc = N  fp  nHZ  fL  fI  fs, the factor Nc is:
 
  A) the number of planets in a solar system.
  B) the average number of stars that have planets.
  C) the average number of planets in each solar system suitably placed in the habitable zone.
  D) the number of technological civilizations in the Milky Way Galaxy with which you might communicate.

Question 3

In the context of astronomy, a habitable zone is:
 
  A) a region on a planet where conditions are acceptable for life to exist.
  B) a region around a star where a planet's temperature would permit the existence of liquid water.
  C) a region on a young planet where amino acids can begin to form deoxyribonucleic acid (DNA) molecules.
  D) a region around a star where different types of planets can form.