1. The principle of cultivating insect-resistant insects is that the reason for fund reorganization is: through fund reorganization, resistant insects can be cultivated and then reproduced in large numbers.

2. Genetic recombination refers to the recombination of genes that control different traits during the sexual reproduction of organisms. It occurs in every generation of diploid organisms.

3. The two copies of each chromosome may have different alleles at some positions. By exchanging the corresponding parts between chromosomes, recombinant chromosomes from different parents can be produced. Recombination comes from the physical exchange of chromosomal material. During the prophase of meiosis, there are 4 copies of each chromosome, and all 4 copies are closely connected and synapse occurs. This structure is called a second-order body, and each chromosome unit of the second-order body is called a chromatid. The pairwise exchange of chromosomal material occurs between different chromatids (non-sister chromatids).