Answer:
A) One band of intermediate density and one band of heavy density.
Explanation:
According to semi conservative model of replication the two DNA strands separate during replication such that the new DNA molecule has one parental strand and one new strand. In this experiment, originally E.Coli cells were grown in 14N medium so all the DNA strands had 14N. When the medium was changed to 15N, only 15N would be available to the cells for replication.
After first round of replication all DNA molecules would be of intermediate density as one strand would be old 14N strand and another would be new 15N strand. After second round of replication 15N strand would be formed from both 14N strand and 15N strand. So, one band will be formed of intermediate density (14N-15N) and another would be of heavier density (15N-15N).
Allele frequency refers to how common an allele is in a population. It is determined by counting how many times the allele appears in the population then dividing by the total number of copies of the gene. The gene pool of a population consists of all the copies of all the genes in that population.
Answer:
Explanation:
In gene transfer, researchers introduce a foreign gene directly into cancer cells or into surrounding tissue. The goal is that the newly inserted gene will cause the cancer cells to die or prevent cancer cells and surrounding tissue from funneling blood to tumors, depriving them of nutrients they need for survival.
Since the population of finches had decreased when deforestation and logging started, and it returned to its original values prior to deforestation when locals started to replating trees, it follows from these facts that trees are being a limiting factor in finches' populations, either because they're acting as niches, food, both or anything else that these populations needed to survive.
Therefore, the correct answer to this question is option D.
