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).
Acid rain. burning fossil fuels releases a form of sulfur into the air which causes acid rain
DNA is the blueprint and rna helps carry out DNA’s blueprint
They cause current to flow through the body to the ground. Low-frequency magnetic fields induce circulating currents within the human body. The strength of these currents depends on the intensity of the outside magnetic field. ... Heating is the main biological effect of the electromagnetic fields of radiofrequency fields.
