45) Suppose there are a million inhabitable planets in our galaxy, that one in ten are habitable, that one in a thousand planets with life at some point had an intelligent civilization, and that one in a hundred civilizations that has ever existed is in existence now. Given this, how many civilizations are in existence now?

48) White dwarfs

8) In this version of Drake’s equation, where N is the

20) Why are there no impact craters on the surface of Io?

1) What other places in the solar system have habitats that might support life?

33) On Saturn’s moon Enceladus, fountains of ice particles and water vapor are seen to be spraying out of

10) Approximately how many exoplanets have been discovered to date?

Name the specific vessels indicated (yellow arrows, A): Name the specific structure indicated (green arrow, B):

Name the structure indicated (A, yellow arrows): Name the type of tissue lining the lumen of the structure indicated (B, green arrows):

Match the indicated structure with the correct answer.