Which of the following is not a source of farm power?

The source of farm power that is not listed is "plough". Explanation: Farm power refers to the energy source used to perform agricultural operations such as plowing, planting, and harvesting. The most common sources of farm power include human, animal, and mechanical power. Wind power can also be used to generate electricity which can be used to power farm machinery. A bull is an example of animal power that can be used for plowing and other farm operations. A tractor is an example of mechanical power that can be used for a wide range of farm operations. A plough, on the other hand, is not a source of farm power but rather a farm tool used for tilling the soil. It can be pulled by animal or mechanical power, but it is not a source of power in itself. Therefore, the correct answer is "plough".