Rotation of crops refers to the practice of growing different crops in succession on the same piece of land. This is done to maintain soil fertility and prevent the depletion of nutrients.

Option 1 is the correct choice as it accurately defines rotation of crops. By growing a variety of crops in a specific sequence, farmers can ensure that the soil is replenished with different nutrients and that the specific needs of each crop are catered to. This helps in preventing the buildup of pests and diseases that are specific to one crop, as well as reducing the risk of soil erosion.

Options 2 and 3 are incorrect as they do not accurately describe rotation of crops. Option 2 suggests growing the same crop repeatedly, while option 3 suggests growing multiple crops simultaneously, which is not rotation but rather intercropping or mixed cropping.

Option 4 is also incorrect as there is an appropriate answer provided.