well because tjey are small and could be transported in ships and in other transportation.
Answer:
Human polygenic inheritance are height, skin color, eye color and weight.
Explanation:
Polygenic inheritance is the set responsible for many characters that appear simple from the surface. Many characters such as weight, shape, height, color, and metabolism are governed by the cumulative effect of many genes.
Polygenic inheritance is not expressed at all as discrete characters, as in the case of Mendelian characters. Instead, polygenic characters are recognized by being expressed as graduations of small differences (a continuous variation). The result forms a curve with an average value at the peak and extreme values in both directions.
Sickle-cell anemia is inherited..It is a condition where there are not enough healthy red blood cells to carry enough oxygen through your body...There is no cure for sickle-cell anemia over time damage is done to your vital organs...
1. natural selection acts on existing traits because you can not evolve into something you didn't have
2. original structures evolve to accomplish new function in order to survive
