Discuss the main reason for the low productivity of ocean.

What is the main reason for low milk production in India ? How can it be improved ?

One main reason for emphysema is

What could be the main reasons for the formation of African and Eurasian desert belt? 1. It is located in the sub-tropical high pressure cells. 2. It is. under the influence of warm ocean currents. Which of the statements given above is/are correct in this context ?