1. What molecules were created in the Miller-Urey experiment?
a) Proteins.
b) Amino Acids.
c) DNA.
d) RNA.
e) Ribozymes.

2. In the Miller-Urey experiment, what were the initial chemicals used?
a) Proteins.
b) Amino Acids.
c) Molecular nitrogen and CO₂.
d) Methane, ammonia, and water.
e) RNA.

3. The early Earth likely had an atmosphere of:
a) methane and ammonia.
b) CO₂ and N₂.
c) oxygen.
d) sulfuric acid.
e) amino acids.

4. Occam's Razor states that:
a. Anything that can go wrong, will go wrong.
b. The simplest hypothesis that fits the data is most likely the correct one.
c. In the ancient past, a species of intelligent extraterrestrials visited Earth and left behind bacteria lifeforms which evolved into more advanced life.
d. Life originated on Mars, then traveled to Earth via meteorites.
e. the larger a planet, the more likely it is to have life.

5. Where is Olympus Mons?
a) On Mercury.
b) On Venus.
c) On Mars.
d) On Ganymede.
e) On Callisto.

6. Pancake domes are found:
a) On Mercury.
b) On Venus.
c) On Mars.
d) On Ganymede.
e) On Europa.

7. The maria on the Moon were formed by:
a) impacts with planetesimals, which cracked the surface and caused lava to flow.
b) the equivalent of sea floor spreading: two continental plates moving apart.
c) two continental plates colliding.
d) volcanism.
e) wrinkling of the surface due to shrinkage of the Moon as it cooled.

8. Radar maps of Venus reveal:
a) a very high density of craters, higher than Mercury and the highlands of the Moon.
b) (possibly) extinct volcanic mountains and hardened lava flows.
c) a gigantic crack in the surface, as long as the continental US.
d) an ice-covered surface, with a possible liquid water ocean under the surface.
e) evidence for large-scale on-going plate tectonics, like on the Earth.

9. Dry river beds from past rivers of water are seen on:
a) all the terrestrial planets and the Moon.
b) all the terrestrial planets, but not the Moon.
c) on only Venus, Earth, and Mars.
d) on only Earth and Mars.
e) on only Earth.

10. The large dark spots one can see on the face of the Moon without a telescope are:
a) very cratered, compared to the rest of the Moon.
b) very mountainous, compared to the rest of the Moon.
c) smooth lava flows.
d) composed of the oldest known rocks in the solar system.
e) about the diameter of the Earth.

11. Observations of Venus in visible light using the Hubble Space Telescope reveal:
a) A very cratered rocky surface.
b) A dark, smooth surface with few mountain ranges.
c) Polar ice caps and evidence of huge dust storms.
d) A completely cloud-shrouded planet.
e) Extremely large volcanic mountains.

12. The light-colored polar caps on Mars are made up of:
a) Sulfur dioxide, and other sulfur compounds.
b) Volcanic outflow of light-colored lava and dust.
c) Water and carbon dioxide ices.
d) Light-colored dust, blown there by intense dust storms.
e) Organic molecules.

13. Which planets or moons show evidence of water erosion?
a) Earth and the Moon.
b) Earth and Venus.
c) Earth and Mars.
d) Venus, Earth, and Mars.
e) All of the terrestrial planets.

14. Which planet or moon is the Messenger spacecraft targeting?
a) Mercury.
b) Venus.
c) The Moon.
d) Mars.
e) Pluto.

15. Which planet or Moon did the Magellan spacecraft map?
a) Mercury.
b) Venus.
c) Mars.
d) Jupiter.
e) Pluto.

16. Which planet(s) have polar ice caps?
a) Mercury, Venus, Earth, and Mars.
b) Venus and Earth.
c) Earth and Mars.
d) Mercury and Earth.
e) Only Earth.

17. On which planet or moon is the Valles Marineris?
a) Mercury.
b) Venus.
c) The Moon.
d) Mars.
e) Phobos.

18. One of the goals of the Messenger mission is to:
a) obtain close-up pictures of the previously unmapped side of Mercury.
b) bring back soil and rocks from Mars.
c) use radar to test whether Europa has liquid water under the icy surface.
d) investigate the magnetic field of Jupiter.
e) take close-up pictures of Pluto.

19. Rovers are currently exploring which planet/moon?
a) Mercury.
b) Venus.
c) Mars.
d) Titan.
e) Mars and Titan.

20. Which of the following is NOT considered a possible argument against life on Venus?
a) a very high temperature.
b) no liquid water.
c) a very high atmospheric pressure.
d) H₂SO₄ in clouds.
e) its thin atmosphere.

21. It has been suggested that there may be extraterrestrial life based on silicon rather than carbon. Why?
a) Silicon is more abundant than carbon in the Universe.
b) SiO₂ is a gas at Earth-like temperatures and pressures, like CO₂.
c) Silicon makes double and triple bonds as readily as carbon.
d) A silicon atom makes four molecular bonds, like carbon atoms.
e) Silicon-silicon bonds are stronger than carbon-carbon bonds, in general.

22. Ribozymes are:
a) Amino acid chains.
b) RNA molecules that are catalysts.
c) Proteins.
d) molecules with iron pyrite in their centers.
e) clay-based life.

23. When a peptide bond is made between amino acids, which molecule is created as a side product?
a) a water molecule.
b) an ammonia molecule.
c) a CO2 molecule.
d) a methane molecule.
e) an ethane molecule.

24. The surface of Venus has been mapped using:
a) the Hubble Telescope using visible light.
b) the Hubble Telescope using ultraviolet light.
c) radio waves from spacecraft.
d) rovers exploring the surface.
e) it has never been mapped; we do not know what the surface of Venus looks like.

25. Which objects have possible dunes on their surface, shaped by wind?
a) Only Earth.
b) Only Earth and Mars.
c) Only Venus and Earth.
d) Only Mercury and Earth.
e) Earth, Mars, Venus, and Mercury.

26. The Andes Mountains in South America were formed by:
a) Two tectonic plates moving apart.
b) Two tectonic plates colliding.
c) Differentiation.
d) A very large meteorite impact.
e) It is unknown what produced the Andes Mountains.

27. On Earth, most of the earthquakes occur:
a) in the centers of the tectonic plates.
b) along the boundaries of the tectonic plates.
c) near the equator, where tidal stresses from the Moon are largest.
d) near the poles.
e) evenly distributed around the Earth.

28. The rocks on the floor of the Atlantic Ocean:
a) are all about the same age.
b) increase in age with increasing distance from the Mid-Atlantic Ridge.
c) decrease in age with increasing distance from the Mid-Atlantic Ridge.
d) all have magnetic fields pointing in the same direction.
e) have never been dated.

29. What produced the Mid-Atlantic Ridge?
a) Two tectonic plates moving apart.
b) Two tectonic plates colliding.
c) Differentiation.
d) A very large meteorite impact.
e) It is unknown what produced the Mid-Atlantic Ridge.

30. The Mid-Atlantic Ridge is:
a) A gigantic crack in the floor of the Atlantic Ocean, caused by an impact with a large meteorite.
b) A place where two tectonic plates are colliding, and one is being pushed up.
c) A place where two tectonic plates are pulling apart.
d) A large mountain on the ocean floor, caused by an object from space smashing into the ocean and forming a mountain.
e) A very old mountain range, leftover from the formation of the Earth.

31. What causes the Earth's seasons?
a) The changing distance of the Earth from the Sun.
b) The cyclic freezing and melting of the oceans.
c) The changing distance of the Moon from the Earth.
d) The 23.5 degree tilt of the Earth's spin axis.
e) The elongation of the Earth's orbit.

32. In a DNA molecule, the base cytosine connects to:
a) adenine.
b) guanine.
c) thymine.
d) cytosine.
e) all of the above.

33. In chemistry, the term `hydrogen bond' refers to:
a) the hydrogen-hydrogen bond in a molecule of H₂.
b) The bonds between hydrogen and carbon in a methane molecule.
c) When hydrogen shares a pair of electrons with another atom.
d) A weak bond between a hydrogen atom in a molecule with an unshared pair of electrons in an atom in another molecule.
e) When two hydrogen nuclei fuse together to form helium.

34. The figure to the right shows part of a DNA molecule. The connection marked by an arrow is called a:
a) hydrogen bond.
b) phosphodiester bond.
c) peptide bond.
d) triple bond.
e) amine bond.

35. In a DNA molecule, the bonds that connect the bases to each other are:
a) hydrogen bonds.
b) carbon-carbon single bonds.
c) carbon-carbon double bonds.
d) phosphodiester bonds.
e) CORN bonds.

36. A fragment of a DNA molecule is shown to the right. The molecule marked by an `A' is adenine; the molecule marked by `T' is thymine, and the molecules marked by `G' are guanine. What is the molecule marked by an `X'?
a) phosphate.
b) deoxyribose sugar.
c) cytosine.
d) guanine.
e) adenine.

37. In the figure to the right, what type of molecule is marked by a `Y'?
a) phosphate.
b) deoxyribose sugar.
c) cytosine.
d) guanine.
e) adenine.

38. In the figure to the right, what type of molecule is marked by a `Z'?
a) phosphate.
b) deoxyribose sugar.
c) cytosine.
d) guanine.
e) adenine.

39. In the figure to the right, what type of bonds connect adenine and thymine?
a) hydrogen bonds.
b) phosphodiester bonds.
c) peptide bonds.
d) carbon-carbon double bonds.
e) nitrogen-nitrogen double bonds.

40. In a human DNA molecule, how many base-base pairs are there?
a) 1.
b) 10.
c) 100.
d) 3 billion.
e) 10²⁷.

41. In a water molecule, how many pairs of electrons is the oxygen atom sharing with other atoms?
a) none.
b) one.
c) two.
d) three.
e) four.

42. Which of the following bonds in a DNA molecule is the weakest?
a) The bonds between the phosphates and the sugars.
b) The bonds between the bases and the sugars.
c) The bonds between two bases.
d) The bonds between the amino acids.
e) The bonds between the amino acids and the sugars.

43. In the double helix structure of DNA, two long strands of molecules are connected by `rungs', like the rungs in a ladder. The strands are sequences of:
a) amino acids.
b) deoxyribose sugar and bases.
c) deoxyribose sugar and amino acids.
d) deoxyribose sugar and phosphates.
e) phosphates and bases.

Answers: 1b, 2d, 3b, 4b, 5c, 6b, 7a, 8b, 9d, 10c, 11d, 12c, 13c, 14a, 15b, 16c, 17d, 18a, 19c, 20e, 21d, 22b, 23a, 24c, 25b, 26b, 27b, 28b, 29a, 30c, 31d, 32b, 33d, 34b, 35a, 36c, 37b, 38a, 39a, 40d, 41c, 42c, 43d.