What happens to the carbon dioxide produced from cellular respiration

a) It's converted into carbon monoxide by the oceans.
b) It's released into space from the atmosphere.
c) It's converted to glucose by plants
d) It reacts with nitrogen to form fossil fuels.

I personally think all of these answers sound ridiculous.. but I'm sure I'm wrong since this is a study guide for my biology test -.-

c. (you use O2 and exhale CO2. Plants fix the CO2 during photosynthesis and release the O2 back into the atmosphere where we breath it in again... chemicals don't come from nowhere!)

Hello,

Cellular respiration is a "catabolic" reaction (breaks down larger molecules like food or glucose in the into smaller components). It's also an exergonic and exothermic reaction b/c it releases energy and heat, respectively (thus CAN be spontaneous if the Activation Energy is reached). The by products (besides energy and heat) are water and carbon dioxide. The CO2 may be used by plants for "photosynthesis" (the opposite of cellular respiration) and convert the CO2 (plus the water that they already possess or have obtained) to glucose and ultimately starch or cellulose. Thus, photosynthesis is an "anabolic" process (b/c opposite of cellular respiration's catabolic process), and will USE energy (from ATP) to synthesize or make glucose. Hope that provides yourself great insight and interest. =D