Which statement best predicts the activity of an enzyme-catalyzed reaction as the concentration of substrate in a sealed flask decreases

Which of the following is an oxidation-reduction reaction? (pictured below)

When it is summer at the south pole, a. the northern hemisphere is tilted toward the sun. b. the southern hemisphere is tilted away from the sun. c. the northern hemisphere is tilted away from the sun. d. both the southern and northern hemispheres are tilted toward the sun.

Describe the process of nociception using the four phases of