The answer is a. mesosphere
Earth’s atmosphere is divided into 5 layer, from the outer layer it will be: Exosphere, Thermosphere, Mesosphere, Stratosphere, Troposphere. The coldest area of the atmosphere would be the middle layer called mesosphere. The average temperature of this atmosphere is −85 °C , a bit lower than stratosphere temperature −60 °C.
<span>The fluid flows through the interventricular foramen into the third ventricle, is augmented by fluid formed by the choroid plexus of this ventricle, and passes through the cerebral aqueduct to the fourth ventricle, which also possesses a choroid plexus. The CSF from all theses sources , as well as any formed in the central canal of the spinal cord, escapes from the fourth ventricle into the subarachnoid space through the median aperture and lateral aperture.</span>
The RNA codon will be GAU, pairing Cytosine-Thymine-Adenine DNA codon with Guanine-Adenine-Uracil RNA codon. This codon is the Amino Acid, Aspartic Acid. In this codon we see Uracil which is the counterpart of Thymine in the RNA.