The four factors that affect evolution are mutations, natural selection, genetic drift and the gene flow, In the case, if the ground finches that Grants studied, we can observe the working of the natural selection. Due to change in the conditions in the environment, the large beak was an advantageous trait that was favored by the natural selection. The result of this process was an increase in numbers of large beaked finches and decrease in small-beaked finches compared to the initial numbers in the population.
Answer:
E. All of the above
Explanation:
In cardiac contractile cells there is rapid depolarization, then a plateau phase and repolarization.
when an action potential stimulates the cell, voltage-gated channels open quickly commencing the positive-feedback mechanism of depolarization. This in turn raises the membrane potential to approximately +30 mV, and this closes the sodium channels. Next comes the plateau phase, where membrane potential declines relatively slowly due to the opening of the slow Ca2+ channels, allowing Ca2+ to enter the cell while few K+ channels are open, leading to K+ to exit. Once the membrane potential reaches approximately zero, the Ca2+ channels close and K+ channels open, allowing the exit of K+. The repolarization lasts approximately for a while and here is when the membrane potential drops until it reaches resting levels once more and repeats the cycle.
Answer:
See the second attached image showing the gametes from the parent with the location of the centromere indicating the type of chromosome
Explanation:
According to the position of the centromere, chromosomes can be of 4 types namely:
- Metacentric
- Acrocentric
- Telocentric
- Sub-metacentric
A metacentric chromosome is a chromosome that has no short or long arm. The arms are equal in length with the centromere joining the two sister chromatids located at the center.
Acrocentric chromosomes have unequal arm lengths with the centromere skewed towards one end of the chromosome.
Telocentric chromosomes have their centromeres at one end of the chromosome.
Sub-metacentric chromosomes have unequal arm lengths but the centromere is not as skewed to one end of the chromosome length as found in acrocentric chromosome.
The only possible gamete from <em>aa bb</em> parent is <em>ab</em>. Recall that the allele <em>a </em>is located on a metacentric chromosome while allele <em>b </em>is located on acrocentric chromosome.
