Why are diseases native to the region where a tree grows, rarely a serious problem?

Need asap plz hurry im being timed when a body cell divides through the process of mitosis, the chromosomes in the daughter cells a. represent only the healthiest chromosomes from the parent cell. b. represent only half of the chromosomes in the parent cell. c. are identical to the chromosomes of the parent cell. d. are formed when chromosomes from the parent cell cross over.