The vector that would be the
best choice for cystic fibrosis gene therapy is adeno-associated virus for it
has valuable reasons. First, it is huge enough to carry the gene, second, it
will infect the right type of tissue, third, it will not cause an immune
response and lastly, it infects the particular cells that divide irregularly. Therefore,
this vector will definitely treat cystic fibrosis for it can target affected
cells, which is a great help in the normal functioning of an organ.
Birds, insects, and many reptiles excrete nitrogenous waste in the form of uric acid, which saves water.
Nitrogenous waste in the body tend to form toxic ammonia, which must be excreted. Mammals such as human excrete urea, while birds, reptiles, and some terrestrial invertebrates produce uric acid as waste in the form of a white paste or power. The production of uric acid involves a complex metabolic pathway that is energetically costly in comparison to processing of other nitrogenous wastes such as urea or ammonia, it has the advantages of reducing water loss and, hence, reducing the need for water.
I hope this can help some.
The answer would be D.: <span>Helicases separate the two strands of the double helix, and DNA polymerases use each of the original strands as templates to create two new strands. :)</span>
