First answer is , as the work of ventricle is to push blood to he whole body , so it has to be strong or it can not pump blood to head to the toe !
as in frog (an amphibian ) it has only three chambers as two artia and one ventricle, so the oxygenated blood from left artia and deoxygenated blood from right , combines and thus partial oxygenated blood is circulated !
Answer:
In terms of adaptation, fitness refers to the ability of an organism to survive and reproduce in a constantly changing environment.
Adaptive traits are very much important in a constantly changing environment as they increase the chances of survival of a population in the environment.
For example, Darwin's finches adapted to develop different types of beaks in order to get nutrition in different environments. Long necks of giraffes are also considered as a result of adaptation which helps them get the food located high on trees.
<span>Human skin color is a polygenic trait, which means that multiple gene loci (with different alleles) are involved in its expression. It has been shown that there more than 350 genetic loci involved in determining skin color. Because of that, there is the enormous number of possible genotypes for the skin color and as a result, the phenotypes vary from the darkest brown to the lightest hues.</span> <span> Different populations have different allele frequencies of genes for human skin color, and the combination of these allele variations brings about complex and continuous variation in skin coloration. Natural skin color can change due to exposure to sunlight (becomes darker) and that is the way it adapts to intense sunlight irradiation (protection against the UV exposure).</span>
