The old saying "one rotten apple spoils the whole barrel" is due to chemical signaling in plants via
A) an increased uptake of carbon dioxide during respiration in target cells.
B) a local regulator for apple development.
C) a release of ethylene gas, a plant hormone for ripening.
D) an a/a cell signal system in the rotten apple.
E) a signal transduction pathway involving glycogen phosphorylase.
Answer: C