he correct answer is number one. A chromosome is composed of many genes. A chromosome is referred to as a DNA molecule in an organism's body, which consists of genetic materials. Chromosomes consists of numerous genes within them, in their nucleus and mitochondria, genes are found inside the Chromosomes itself
Species have similar characteristics, but they are rarely, if not never, identical; the difference between them is variation!
Hope this helps! :)
I would say 1 and 4 are the best answers. GMO crops are clones (genetically identical) so it reduces the genetic diversity making crops susceptible to new diseases.