Question

Plants produce carbohydrates for themselves through the process of photosynthesis. Which cycle is carried out when these carbohydrates are passed on along the food chain to animals and other consumers?

A. The nitrogen cycle B. The phosphorus cycle C. The carbon cycle

Answer 1

The carbon cycle. Although it's not specific, it talks about combustion or respiration. The reason I chose the carbon cycle, is because nitrogen DOES appear in photosynthesis, but you were strictly talking about carbohydrates. 

Answer 2

Among the choices listed it is the carbon cycle and the nitrogen cycle are the best candidates because they both are involve in the process of photosynthesis. However, I think it is the carbon cycle that involves carbohydrates rather than the nitrogen cycle.