Mixed farming refers to a farming practice where multiple agricultural activities are carried out simultaneously. In option 1, it is stated that mixed farming involves growing several crops in a planned way. While this is partially correct, it does not encompass the entire concept of mixed farming. Option 2 suggests that mixed farming involves growing both Rabi and Kharif crops. Although this is a part of mixed farming, it does not fully explain the concept. Option 4 states that mixed farming involves growing fruits and vegetables, but this is a limited view of mixed farming.

The correct answer is option 3, which states that mixed farming involves growing several crops and also rearing animals. This option presents a more comprehensive explanation of mixed farming. In addition to growing various crops, mixed farming also includes the rearing of animals such as cattle, poultry, or sheep. This combination of crop production and animal rearing allows for a diversified and sustainable agricultural system. Mixed farming helps in maximizing land utilization, increasing productivity, and providing a stable source of income for farmers. It also facilitates the efficient use of resources, as different agricultural activities complement and support each other. Thus, option 3 is the most accurate description of mixed farming.