Sit on the floor with your legs straight out, raise your straight arm out with your thumb up such ...

Sit on the floor with your legs straight out, raise your straight arm out with your thumb up such that your thumb aligns with one of your big toes, rapidly blink your left and right eye, and observe how your big toe appears to shift positions. This demonstration is an example of _________________.
 
  a. Newton's first law b. uniform circular motion
  c. parallax d. retrograde motion

Question 2

The energy generated by the Sun is released by the _______ to make _______ nuclei.
 
  a. fusion of H nuclei; He
  b. fusion of He nuclei; H
  c. fission of H nuclei; He
  d. fission of He nuclei; H

Question 3

If the period of a body's orbit is doubled, then the distance from the host has ___________. Assume the units of period are years and the units of distance are A.U. Choose the best answer.
 
  a. doubled b. halved
  c. stayed the same d. increased by about 1.5 times