1) Seeding depth depends on the size of the seed (and soil properties)
2) The larger the seeds, the deeper they sow, because large seeds have more reserve substances and they are enough for the development and growth of seedlings, while they make their way from great depths. Corn and bean seeds are larger, so they are sown deeper.
3) Seeds of poppy and carrots are small, contain a small supply of nutrients. If such seeds are sown deeply, then the plants developed from them will not be able to break into the light due to lack of nutrients.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.