The DNA is read by RNA Polymerase which then makes an exact match of the non-coding strand of the DNA into a RNA molecule - messenger RNA or mRNA...which is then read and transcribed by the ribosome into a protein.
The DNA carries all the information of heredity of all living organism. In humans, DNA can be found in multiple cells that have a nucleus such as blood cells, saliva, sperm, etc. These are the target cells in forensic studies.
The DNA varies from person to person, making it unique (except for identical twins, the DNA are practically the same). This is because one chromosome of each pair comes from the mother and the other comes from the father and could have millions of combinations. Typing the DNA, we can know the variants in each person and match with a suspicious person’s fluids in a crime scene.
I believe the most appropriate answer is a. optic chiasm
From retina, the optic nerve will go to optic chiasm where it will go to the lateral geniculate nucleus and medial colliculus. Medial colliculus will go to the superior colliculus, while lateral geniculate nucleus goes to the visual cortex. Optic nerve is decussating/crossing at the optic chiasm, not the corpus callosum. Anterior commissure also irrelevant to the visual tract.
B. It has mitochondria and is a member of the domain Eukaryota.
Eukaryota cells can form snglie celled or multicelled organisms, but what makes them Eukaryota is the fact that they have a nucleus where they store all of the DNA of that cell, it also means that if it is a Eukaryota cell it has to have a mitochondria to carry out the functions of energy conversion in the cell, so the best option would be B. It has mitochondria and is a member of the domain Eukaryota.
Identical twins may have the same DNA, hence their nature will be the same. However, the character of the different twins may vary because of variations in nurture. This is described as epigenetics which is the effect of environmental stimuli on genetic material without its change in sequence. This affects gene expression due to the differences in DNA methylation and histone modification profiles between the twins.
Since the resulting nucleotide is offset from its initial sequence by only one parallel nucleotide we can definitely say it is Missense mutation. This sort of a mutation is known as a nonsynonymous mutation, there is only one direct substitution that occurs in the codon producing a different amino acid.