Question

the main focus of sustainable agriculture is: increasing land usage efficiency maintaining long - term land productivity using synthetic chemicals maximizing short - term yields

Explanation:

Sustainable agriculture aims to meet the needs of the present without compromising the ability of future generations to meet their own needs. It focuses on long - term viability. Maintaining long - term land productivity ensures that the agricultural land can continue to produce food and other products over time, which is a key aspect. Increasing land usage efficiency is important but not the main focus. Using synthetic chemicals is often contrary to sustainable practices as they can harm the environment. Maximizing short - term yields may lead to over - exploitation and is not sustainable.

Answer:

maintaining long - term land productivity