Think of blood as a gas/ fuel for the car ( your body). If there is no fuel, there's no movement (dead) so when the fuel tank is damaged the car won't function properly.
So if the heart becomes damaged, or weakened it would start making blood clots and damage the organs that need blood to function properly. The circulatory system wouldn't function properly and because other organs depend on the circulatory system it would cause a chain reaction, affecting other body systems. <span />
Answer:
Variation can be acted on by natural selection.
Explanation:
Variation are the difference that exist in the organism in terms of the body size and can be acted upon by natural selection.
Natural selection could act on the owl body size, favor the selection of owl with small body size especially when resources available are limited and can only sustain small number of individuals leading to availability of owl with small body size in such area and a gradual reduction in the number of owl with large body size.
Species A and B would be the most similar because there is only one mutation between the two of them located in the first codon.