During the Period, great swamps covered North America and parts of Europe. This period got its name because it was the beginning of our great coal deposits. During this Period, the amniotic egg developed and the first true reptiles appeared on Earth along with winged insects.

The gene that causes sickle-cell disease is present in a higher percentage of residents of sub-saharan africa than among those of african descent living in the united states. even though this gene causes sickle-cell disease, it also provides some protection from malaria, a serious disease that is widespread in sub-saharan africa but absent in the united states. discuss an evolutionary process that could account for the different percentages of the sickle-cell gene among residents of the two regions.

The first signs of cellular differentiation occur in the blastocyst. why is cellular differentiation important for the development of a fully formed human infant?

Kelly ran electricity though a sample of water using electrolysis. the water changed into two gases, x and y. it was not possible to break down the gases x and y into simpler particles.