Answer:
Explanation:
1. Most cancers arise from defects in DNA. True defects in the DNA including mutations can lead to cancer.
2. The presence of a single mutated gene is sufficient for retinoblastoma cancer to develop. False: the presence one mutant copy of the gene of RB1 is not sufficient enough to cause cancer
3. miRNAs play a critical role in initiating tumor development. True: MiRNAs may function as either oncogenes or tumor suppressors under certain conditions. They have been shown as biomarkers for human cancer diagnosis.
4. A single gene mutation may predispose a person to developing cancer. False: many mutations in the cells coupled with other risk factors may predispose a person to developing cancer
5. Overactive telomerase enzyme deletes the ends of chromosomes and can cause cancer. False: Instead the enzyme just keeps adding more and more repeats to the telomereres and the cancer cell can keep dividing without losing DNA and genes at the ends of the chromosomes
6. Relatively few people inherit all of the genetic changes that cause cancer: True: there are some genetic changes that are not inherited but acquired.
7. Proto-oncogenes do not cause cancer. True: they do not cause cancer but a mutation in them might lead to the activation of oncogenes that causes cancer.
8. Most tumors arise from germ-line mutations that accumulate during our life span. False: most common cancers are as a result of somatic or acquired mutation that have accumulated during our life span. Germline mutations are hereditary
9. Xeroderma pigmentosum includes predisposition to cancer due to defects in a specific DNA repair system.
True: a defect in the DNA repair system paritcularly in enzymes invloved in this repair
Answer: A. the lens focuses light on the retina
The lens is composed of transparent, flexible tissue and is located directly behind the iris and the pupil. it is the secondary part of the eye after the cornea. by changing it's shape the lens changes the focal distance of the eye and focuses the light that passes through it and into the retina in order to create clear images of objects. it also works together with the cornea to refract, or bend light.
good luck and a great day to you.
Answer: the right aswer is <u>B. Its phenotype is better suited to its environment.</u>
Explanation:
I know this because i just had a quiz and the answer above me is completely wrong. and if some of you dont think its B, then you can go with <u>C. It will live longer than most other individuals. </u>
Stay safe and Stay smart people.
That 123456789010qwertyuiopasdfgghjklzxcvbnm have a nice day says my keyboard
