Photosynthesis in c4 plants is relatively less limited by atmospheric CO2 levels because CO2effectively pump in bundle sheath cells. Therefore little or no chance of photorespiration and CO2 is not a limiting factor for c4 plants.

Explanation:
C4 plants are more efficient in photosynthesis than C3 plants due to lower rate of photorespiration. This is because C4 plants have a special mechanism to reduce photorespiration. Let's understand this mechanism in detail.

C4 Plants:
C4 plants are a group of plants that have adapted to a hot and dry environment. They are called C4 plants because they have a special pathway for carbon fixation known as the C4 pathway. In this pathway, carbon dioxide is first fixed into a four-carbon compound, before it is converted into the three-carbon compound in the Calvin cycle.

Photorespiration:
Photorespiration is a process that occurs in plants when they take in oxygen instead of carbon dioxide during photosynthesis. This results in the release of carbon dioxide and energy, which reduces the efficiency of photosynthesis.

Lower Rate of Photorespiration:
C4 plants have a lower rate of photorespiration because they have a special mechanism to reduce it. In C4 plants, the initial fixation of carbon dioxide into a four-carbon compound occurs in the mesophyll cells, which are located near the surface of the leaf. The four-carbon compound is then transported to the bundle sheath cells, which are located deeper in the leaf. In the bundle sheath cells, the four-carbon compound is converted into the three-carbon compound, which is then used in the Calvin cycle.

This separation of the initial carbon fixation and the Calvin cycle in different cells reduces the oxygen concentration in the mesophyll cells, which reduces the rate of photorespiration. This is because oxygen is produced in the bundle sheath cells during the conversion of the four-carbon compound into the three-carbon compound, which reduces the oxygen concentration in the mesophyll cells.

Therefore, C4 plants are more efficient in photosynthesis than C3 plants due to their lower rate of photorespiration.