Human activities in the recent past have caused the increased concentration of carbon dioxide in the atmosphere, but a lot of it does not remain in the lower atmosphere because of [2011]

Human activities in the recent past have caused the increased concentration of carbon dioxide in the atmosphere, but a lot of it does not remain in the lower atmosphere because of

its escape into the outer stratosphere
the photosynthesis by phytoplankton in the oceans
the trapping of air in the polar ice caps

Which of the statements given above is/are correct?

1 and 2 only
2 only
2 and 3 only
3 only

Explanation

Only statement 2 is correct

Human activities have significantly increased the concentration of carbon dioxide (CO₂) in the atmosphere; however, a considerable portion of it does not remain in the lower atmosphere primarily due to the absorption by phytoplankton (primary producers) in the oceans through the process of photosynthesis.
Phytoplankton act as a major carbon sink, removing large amounts of CO₂ from the atmosphere.

Illustration of ocean carbon cycle showing CO2 exchange between land, ocean surface, and atmosphere, highlighting biological pump processes like phytoplankton photosynthesis, microbial respiration, and zooplankton grazing. Diagram uses arrows and labels in yellow and white to depict carbon flux, emphasizing ocean's capacity to hold 50 times more CO2 than atmosphere.