Answer:
Grey and White Matter.
Explanation:
When looking at an image of trasnverse section of the spinal cord the grey matter is almost butterfly shapped and it has the central canal in the middle. The white matter is surrounding the butterfly shaped, grey matter.
I believe the answer is a. crossing over
The codon guanine - adenine - cytosine will code for the the amino acid ASPARTIC ACID. The genetic code is represented as an RNA codon table because it is mRNA that direct protein synthesis which take place in the ribosome.
If i'm not mistaken, it's the aorta