Answer:
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 the carbon cycle. Respiration happens all the time, but dominates during the colder months of the year, resulting in higher CO2 levels in the atmosphere during those months.
Explanation:
The answer does the question is : C
They're celled subsistence farmers, their farming practice is subsistence farming, where most of the product they grew or reared are for themselves and their families, they usually don't take the products to the markets for commercial purposes, instead those who do that are practising commercial farming.