The answer is that <span>all
veins carry blood back to the heart, except for the pulmonary vein. the
vena cava empty into the right side of the heart, so they technically
bring blood to the
</span>main atrium.
D Pastureland - Grazing Livestock
Reproductive isolation. Species refer to the group of organisms which share common morphological features and can interbreed and produce a viable offspring. Thus, the organisms of one species are reproductively isolated from the organisms of other species