Answer Happy

20. The normal house-mouse (Mus) lives ~ 1.5 years; the naked mole rat lives – 35 years. Both are in the rodent family; both are about the same size/weight. Cancer incidence in naked mole rats increases dramatically around 30 years of age whereas in Mus it increases when they are only about 15 months old. Why do cells in these two otherwise similar species differ so much in their rate of onset of cancer susceptibility? a. Naked mole rat cells live longer than Mus, so they undergo fewer and slower replication cycles than do mouse cells. Therefore, they have less probability to become a cancer. b. Naked mole rats have fewer total cells, although they are bigger, than does Mus, so the probability of having a cell become cancer is lower. c. Naked mole rats are sexually and reproductively active until a much later age than Mus. To support this, they have evolved stronger anti-cancer defenses than have Mus, which much more effectively protects them from cancer. d. Naked mole rats have low levels of oxidative stress and more active antioxidant systems than does Mus, which protects them from cancer. e. Naked mole rats age slower than Mus, and cancer incidence increases with aging.