The right answer is D.
Gene therapy is a method of introducing nucleic acids (DNA or RNA) into the cells of an organism to correct an abnormality, such as a mutation, causing a pathology.
It is often a question of bringing a normal and functional gene (transgene) into a cell where the present gene is altered.
Another method can bring RNA capable of partially regulating or blocking the expression of an altered gene.
The ice stays on top because it is sold which means it is less dense than liquid (water)
Release of a neurotransmitter across the synapse is triggered by the entry of Ca++ into the presynaptic axon. No Ca++ entry means no transmission across the synapse.
Answer:
The main function of viagra is to relax the muscles of the blood vessels in some areas of the body. It is used for the treatment of erectile dysfunction and for high blood pressure. The component of viagra is a competitor to the enzyme PDE5, breaking down cGMP. In the penis, blood is trapped, which results in the erection being maintained. When cGMP levels decrease, the concentration of calcium ions increases, causing smooth muscle contraction.
Explanation: