The answer to this question is b carpel that's the answer
When a bend in a river gets cut off...
Mitral valve prolapse severe enough to cause regurgitation may directly cause INCREASE pressure in the LEFT atrium. Mitral valve prolapse is a medical condition in which the the two valve flaps of the mitral valve do not close properly, bulging upward into the left atrium. The condition may be mild or severe. Heart surgery may be required in case of the severe one.
The correct answer is option A- HIV virus.
HIV virus is an example of enveloped virus, that has the ability to infect a host cell by attaching itself to it and fusing with the host cell. Once infected, the virus leaves the host cell and moves to another cells to infect them. The HIV virus contains glycoprotein spikes to attach to the host cell.