Assuming the carbon cycle is a closed system, which of the following statements is true?

Question:

Assuming the carbon cycle is a closed system, which of the following statements is true?

A. Mass and energy are conserved in the carbon cycle.  

B. As population sizes increase, more carbon is produced.  

C. When all the fossil fuels are used up, there will be no more carbon.  

D. The Sun absorbs energy from the carbon cycle.    

Answer:

A. mass and energy are conserved in the carbon cycle.

Explanation:

Carbon is always taken as closed system where neither any gain of energy or lost of it can be seen. It can just be transferred from one type to another. This can also be concluded as the energy being transferred to the atmosphere and comes back to the surface of the earth. As we know that the planets and the atmosphere together constitute a closed surrounding, so as the amount of carbon will not change, just change its form.

the sphincter muscles at the end of the digestive tract is the anus.

i believe it would cause an increase of percipitation, though i could be wrong. so i would say b is the answer.