Why does the concentration of CO2 go up and down throughout the year?

the role of plants in carbon cycle

Explanation:

the amount of CO2 found in the atmosphere varies over the course of a year. much of this variation happens because of the role of plants in carbon cycle...respiration occurs all the time, but domains during the colder months of the year, resulting in higher CO2 levels in the atmosphere during those months.

ya the other dude is right

thats not even an aswer choice