Answer:
8. D
9. A
10. A
11. C
12. D
Explanation:
8. Natural selection works on variation that exists in the genes of organisms. Antelopes who have genetic variation that makes their legs more muscular are at an advantage because they can outrun predators. This increases the chance that they will reach reproductive age, and be able to pass this advantageous trait onto their offspring. Over time, this selection pressure makes the variant more common in a population.
9. Beneficial traits are those that give a selective advantage. This could be one that helps it outrun predators (like above), avoid illness and death, gives it a reproductive advantage (i.e. more attractive to mates), or makes it better able to digest certain foods, for example. The formation of cancer cells would be harmful for an organism, reducing its fitness and perhaps leading to death. The inability to reproduce would mean genetic info is not passed on to the next generation, and stopping the production of an essential protein would likely lead to death. However, resistance to a virus would help an organism avoid illness and death, improving fitness.
10. Genotypes are what organisms inherit from their parents, i.e. the genetic information that is passed on. However, the way in which different alleles interact and are expressed is the phenotype. If we take the above example, natural selection is acting on the phenotype of muscular legs. If an antelope had the muscular leg genotype but for some reason it was not being expressed (maybe another gene is interfering with it), then the antelope would not have a selective advantage, and natural selection could not be act on the trait.
11. A trait that better suits an organism to its environment will be selected for by natural selection. This is because that organism is more likely to survive due to the trait, giving it a selective advantage. Therefore, if a mutation arose making the giraffe more adapted to the environment, it would be positively selected for, and through evolution would become more common.
12. This is an example of selective breeding, which has been happening for generations. Farmers spot desirable traits, and cross horses with these traits in an attempt to enhance the trait or to ensure it is passed on to the next generation. This is not natural selection, because farmers are making it happen artificially. It is not cloning or recombinant DNA, which are terms scientists use for actually manipulating the DNA in the lab.
The tricuspid valve, located between the right atrium and the right ventricle; the pulmonary (pulmonic) valve, between the right ventricle and the pulmonary artery; the mitral valve, between the left atrium and left ventricle; and. the aortic valve, between the left ventricle and the aorta.
Answer:
The correct answer is option (e)-"All of the answer choices are correct".
Explanation:
Fossils are defined as the remains of ancient organisms. Fossils are obtained from impressions left after an organism decays. There are different kinds of fossils depending on the material they are made of and how they were formed. Some fossils are made from minerals that are the replacement of the organic matter of the ancient organism, or are the replacement of mud that came from footprints. Alternatively, fossils could be plant resins or tar that preserved a specimen within.
The answer is an overhunting.
<span>The bottleneck event means drastic reduction of the population size because of environment changes. The consequence of this is the reduction of genetic variation. The bison population is a good example of the population bottleneck. The bison population drastically reduced its size due to overhunting which culminated at the end of the 19th century, when bisons almost extinct. </span>
An air mass bringing dry, frigid winds to North Dakota
