I guess so it can be easier to understand. sorry if this wrong im sorry . but this is my answer
Answer:
<em>In heart valve disease, one or more of the valves in your heart doesn't work properly. Your heart has four valves that keep blood flowing in the correct direction. In some cases, one or more of the valves don't open or close properly.<u> This can cause the blood flow through your heart to your body to be disrupted.</u></em>
<span>I think the answer is Three membranes. </span>
Hypotonic - the inside of the cell
Hypertonic - the beaker
Its A because dolphins like to fallow boats not to be scared