1, the principle of cultivating insect resistance is the reason for fund reorganization: cultivate insect resistance through fund reorganization, and then multiply in large numbers.

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

3. Two copies of each chromosome may have different alleles in some positions. By exchanging the corresponding parts between chromosomes, they can be produced by recombinant chromosomes of different parents. Recombination comes from the physical exchange of chromosomal material. In the prophase of meiosis, each chromosome has four copies, and all four copies are closely connected, resulting in synapses. This structure is called diploid, each chromosome unit of diploid is called chromatid, and the exchange of chromosome material takes place between different chromatids (non-sister chromatids).