Question

the yield of greenhouse crops is higher than that of field crops due to increased photosynthetic activity by the plants. which two of the following factors most likely contribute to this? humid air and moist soil conditions rotation of plants constant application of farmyard manure higher than average carbon dioxide levels

Explanation:

Photosynthesis requires carbon - dioxide. Higher CO₂ levels in greenhouses can boost photosynthetic activity. Also, humid air and moist soil can support plant physiological processes related to photosynthesis such as gas exchange and water - nutrient uptake. Rotation of plants mainly helps with soil health and pest management, not directly photosynthesis. Constant application of farmyard manure is more about long - term soil fertility rather than immediate photosynthetic activity.

Answer:

A. Humid air and moist soil conditions
E. Higher than average carbon dioxide levels