Answer:
I am pretty sure that the answer is A.
Explanation:
Protein kinases regulate the cell cycle by giving the "go-ahead" or "stop" signal at checkpoints in the cycle. A mutation/disruption in the protein kinases can result in it not doing its job properly. As a result, it can give the 'go-ahead' signal to all cells (mutated or not) to continue through the cell cycle. A distrupted kinase will infleunce the enviornment for a cancer cell as the cancer cell can continue to divide continuously.
I do not think the answer is D because G-couped receptirs are not involed in the regulation of the cell cycle. Additionally, I do not think the answer is C since the production of cAMP (a secondary messgenger amplifies transduction signals; this doesn't have anything to do with cancer?) Finally, between A and B I know that a direct result of cancer is due to a distruption in either protien kinases or growth factors (not in the answer choices). Since one of the factors that leads to cancer is present in answer choice A, I think that is the one. However, this is just my reasoning, I am not 100% sure!
The epiglottis. It prevents food from entering the respiratory tract
Answer:
When a phenotype produced by certain alleles helps organisms survive and reproduce better than their peers, natural selection can increase the frequency of the helpful alleles from one generation to the next – that is, it can cause microevolution.
Explanation:
