Answer:
Water is a limited resource. It is needed for all living things and must be managed well to ensure we have enough for our needs and to protect our environment.
<span>A substance<span> is a pure form of matter that contains only one type of atom or molecule. It can be further divided into two sub-categories: elements and compounds.</span> The types of substances that most readily diffuse through a cell membrane, however, are the nonpolar and small <span>polar molecules like carbon dioxide and <span>oxygen. These two </span>molecules<span> simple diffusion of water through the membrane thru a process known as osmosis.</span></span></span>
The only correct answer in this case is B - a stroke.
None of the other answers could be counted as correct here.
While A - a heart attack is conceptualy similar, when we're talking about a heart attack, we're talking about not enough oxygen that gets delivered to the heart - because something is blocking it.
C - hypertension on the other hand means someone has a higher blood pressure than is usual for a regular human being, which puts more strain on his cardiovascualr system.
and D - atherosclerosis doesn't come even close to be correct :)
