<span>The physician is opting to use chemotherapy as a backup plan, as cancer may have spread throughout the body before the tumor in the pancreas was removed. Chemotherapy has been proven to treat cancer.</span>
Answer:
Natural selection is an adaptative mechanism that modifies gene frequencies (allele frequencies) in the whole population across generations
Explanation:
According to the evolutionary theory proposed by Darwin, natural selection is the main process that leads to evolution. Natural selection can be defined as a mechanism through which populations adapt and change. The organisms better adapted to their environment will have more chances to survive and reproduce, and therefore they will pass their genes (and favorable traits) to the next generation. This process is able to modify the allele frequencies in the whole population, thereby changing and adapting (i.e., evolving) across generations.
No, but you can always turn to google, or ask a relative as they may be more experienced.
Blood flows to the brain through the internal carotid and vertebral arteries and away from the brain through the internal jugular vein. The internal carotid artery supplies the brain, while the external carotid nourishes other portions of the head, such as the face, skull, scalp and the meninges. The vertebral arteries provide supply to the upper spinal cord, brainstem, cerebellum, and the posterior part of the brain.
