Courts allow patenting complementary DNA (cDNA) because: its exact sequence is not in the genome of an organism. it cannot be synthesized in a laboratory. it is present only in adult humans. it represents only the introns of a gene. Cancer does not typically follow a Mendelian pattern of inheritance because it is usually caused by two gene variants, one dominant and one recessive, and no environmental input. specific combinations of alleles and an environmental factor. specific combinations of an environmental factor and one dominant gene variant. environmental insults and no genes at all. genes that cause death before birth. The logic behind polar body biopsy is based on: Darwin\'s theory of natural selection. Mendel\'s law of segregation. Mendel\'s law of independent assortment. the rules of the central dogma. the idea that the alleles in a polar body are the same as those in the oocyte to which it was attached. Which of the following is a characteristic of cancer cells? Shortening of telomeres Inactivation of oncogenes Activation of tumor suppressor genes Somatic mutations Slowed rates of cell division Solution 17- correct option is 1. Since cDNA does not exist in the cell, it is a synthetic form of an RNA, it can be patented. A cell contains the gene with introns in the form of DNA and codes an RNA with and without introns. cDNA is not synthesized within the cell. So it can be patented. 18- a specific combination of alleles and an environmental factor. Many times the oncogenic allele of a gene is present but it can not cause cancer because other partner genes are non- cancerous alleles. Even if all the oncogenic alleles are present, cancer may not be caused without environmental factors such as stress. 19- Mendel’s laws of segregation. Based on the polar body, the viability of egg can be predicted as the genome complement of the egg cell can be predicted. On comparing with the maternal genome, the frequency of occurrence of maternal side alleles in the egg can be predicted. 20- Shortening of telomeres. Cancer cells initially shorten their telomeres and then express telomerase to maintain those shortened telomeres..