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.
Answer;
Insulin and the growth hormone
The hormones that are involved in building and maintaining healthy bone tissues are Insulin and growth hormone
Explanation;
Insulin has some anabolic properties for bone. It is uncertain whether insulin stimulates bone directly or indirectly by increasing muscle work and thus skeletal loading.
Growth hormone is a peptide hormone secreted from the pituitary gland under the control of hypothalamus. It directly and through IGF-I stimulates osteoblast proliferation and activity, promoting bone formation. Additionally it stimulates osteoclast differentiation and activity,promoting bone resorption.
Africa is the only place where giraffes live in the wild
It would be GCGATT. C always compliments G and A always compliments T in the case of DNA coding
