Differentiate between subsistence farming and commercial farming .

only 2 points:)

Difference between subsistence farming and commercial farming

Explanation:

Subsistence farming is done basically to feed the farmers family itself. It has little or no profit.

Commercial farming is done with the intent of profit, where cash crops are sown.

well, that's easy; the answer's c, "it reduces contamination of the water and substrate of the estuary."