The production of carbon dioxide might be an indicator of what process

The carbon dioxide is produced by two methods naturally, which is either photosynthesis or by decomposition. The indicator thus for the carbon dioxide production be the decomposition most likely.

Explanation:

The carbon dioxide is produced by the process of decomposition and photosynthesis both. But in the process of photosynthesis it is released as a by product which then consumed in the process of respiration. Therefore if there is ample production, it indicated of decomposition. The decomposition is the decaying process of organic matter.

c) up is the direction the magnetic force is acting on the charge.