Answer: creating an ozone layer to shield life from UV rays
Cynobacteria or blue green algae is the strain of bacteria, which was able to produce oxygen in the primitive earth as a result of photosynthesis. The abundance of oxygen in the atmosphere formed the ozone layer in the upper atmospheric layers, these layers are protective enough to provide a shield against the harmful UV radiations incident on earth coming from the sun.
The given case says that a girl was playing with marbles. The marble got stuck in her nose. In this case, the marble is a foreign body, which needs to be removed. The doctor performs the removal of foreign particle from her nose by surgical processes, and he uses hemostats.
The CPT code 30300 is used when a doctor removes the foreign body part from the nose.
The Icd-10-cm code for foreign body in nostril is T17.1, and T17.1XXA is a billable/specific code.
DNA is a long fiber construct that looks like a strand of hair, and a chromosome is a product of DNA.
''So, what do you understand by DNA anyway? DNA can be described as a long fiber that resembles a hair under a powerful microscope. The only difference is that they are much thinner and longer. The whole structure is made of two strands that are intertwined together. When cells get ready to divide, proteins attach themselves to the DNA and leads to the creation of a chromosome.
A chromosome is simply the product of the DNA and the proteins that are attached to it. There are 23 pairs of the chromosomes in every human being. One set is inherited from the father, and one set is inherited from the mother. A DNA is a sort of a bio molecule. The entire DNA in cells can be found in individual pieces that are called chromosomes.
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Hope i helped :)
Source: http://www.differencebetween.net/science/health/difference-between-dna-and-chromosome/