Sahelanthropus tchadensis is believed to be one of the oldest and ancient known species of the family tree of humans. They lived on this planet around 6 to 7 billions years ago. They are the extinct species of Homininae. This fossils of this species were discovered and announced in the year 2002. Some of the important features of this species are :
-- they have prominent brow ridges
-- they were found in the Central America
-- they lived during the time of human chimpanzee divergence
Water, carbon dioxide, and oxygen are among the few simple molecules that can cross the cell membrane by diffusion (or a type of diffusion known as osmosis ). Diffusion is one principle method of movement of substances within cells, as well as the method for essential small molecules to cross the cell membrane.
