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 :)
Answer:
B. It shows how organisms change over time.
Explanation:
embryos can not be observed in fossils.
Proteins are degraded so thats why they can not be studied.
Organisms can not be evolved instantly.
Answer:
The blank box (represents air)
Explanation:
The animal is biotic (living), the tree is also biotic (living), and the piece of wood also biotic (living.) The only abiotic factor in the photo, although we cant physically see it, is air.