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.
Chloroplast is responsible for using light energy to produce sugar. It is located at the top of the leaf because that's where it will absorb the most light while it's still being protected from damage by the cuticle and the epidermis
Semen creates a(n)<u>alkaline </u>environment for sperm to safely travel through both the male and female reproductive tracts.
In the field of biology, semen can be described as a white, slippery fluid that is released from the male reproductory organ. Semen is also referred to as the seminal fluid.
The semen of males carries the sperm cells which are required for the fertilization of the female egg. The conditions should be favorable for the process of fertilization to occur.
The natural atmosphere of the vagina of a female is acidic in nature. The sperms need a neutral environment for survival. Hence, the semen is produced alkaline in nature to prolong the lifetime of sperm cells. The alkalinity of the semen neutralizes the acidity of the vagina.
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No, but we share a common ancestor.
