Explain why in China in the middle of the twentieth century. after the destruction of sparrows, the grain yield dropped sharply. After all, sparrows are granivorous birds.
adult sparrows feed mainly on seeds, but chicks need protein food for their development. Feeding their offspring, sparrows collect a huge number of insects, including pests of grain crops. The eradication of sparrows caused outbreaks of pest breeding, which led to a reduction in the yield.
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.