The answer to this question is A
Answer:
Unlike typical mammalian red blood cells, those from amphibians, such as frogs, contain a DNA-bearing nucleus that is visible in the center of the cell. The circulatory system of amphibians is rather unusual, their hearts having three chambers, two atria, and a single ventricle.
NegativePositive
Positive
The design of the amphibian circulatory system is curious because blood accumulates oxygen in the lungs and is then returned to the heart before being pumped into the rest of the circulatory system. Therefore, a mixing between oxygenated and deoxygenated blood occurs as blood returning to the heart from the lungs is mixed with incoming blood from the body. Frogs handle this situation by having a very slow metabolism and by absorbing some oxygen through their skin. In addition, the ventricle does have some directional control over the distribution of the blood.
Negative
The presence of a nucleus in amphibian red blood cells allows researchers easy access to large quantities of amphibian DNA. Frog blood has both a solid and a liquid portion. The liquid plasma carries solid elements such as red and white blood cells. Blood can be collected from frogs and the red blood cells isolated by centrifugation. After removal of the residual plasma, purified cells can be treated with specific enzymes and detergents to digest the cellular envelope and release DNA from its protein complex. The DNA is then useful for scientific studies and experiments.
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Explanation:
Scientists use triangulation to find the epicenter of an earthquake. When seismic data is collected from at least three different locations, it can be used to determine the epicenter by where it intersects. Every earthquake is recorded on numerous seismographs located in different directions. Each seismograph records the times when the first (P waves) and second (S waves) seismic waves arrive. From that information, scientists can determine how fast the waves are traveling. Knowing this helps them calculate the distance from the epicenter to each seismograph.
To determine the direction each wave traveled, scientists draw circles around the seismograph locations. The radius of each circle equals the known distance to the epicenter. Where these three circles intersect is the epicenter.
Answer:
p53 helps the cells from passing on mutations that lead to DNA damage. Hence, it is known as the guardian angel of the cell as it helps fight against cancer. However, if p53 becomes defective or missing, then the mutations will lead to cancer.
Mutations in the p53 can also cause the tumor-suppressing genes to convert into tumor causing genes. Hence, mutations in such kind of genes can be very harmful for the body.
A human with heterozygous genotype can have a dominant phenotype if one of the alleles complete mask the effects of the other.
- Heterozygous genotype involves two different alleles, unlike homzygous genotypes in which the alleles are the same.
- When the two alleles of an heterozygous genotype exert equal effects on one another, they are said to be codominant.
- When one of the alleles of an heterozygous genotype incompletely exert its effects on the other allele, it is said to be incomplete dominance.
- When one of the alleles complete dominates and masks the effects of the other allele, it is said to be dominant.
Hence, a dominant allele will always produce a dominant phenotype even if the genotype of the organism is heterozygous.
More on genotypes can be found here: brainly.com/question/14398652
