Identify the important features of the pre-australopithecine Sahelanthropus tchadensis. Features of Sahelanthropus tchadensis

prominent brow ridges      

Explanation:

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

c. earths continental crust is thicker than its lithosphere.

because, the lithosphere is the outermost layer of the earth/ 100 km thick and is defined by its machanical properties.the lithosphere contains oceanic and continental crust that varies in age and thickness across locations and geologic time. the lithosphere is the coolest layer of the earth in terms of temperature. the term lithosphere should not be confused with the use of "geosphere" which is used to indicate all of earth systems, including the atmosphere, hydrosphere   and biosphere. the surface of the earth can be divided into the continental crust and the oceanic crust.   the continental crust is made mostly of granite while the oceanic crust is made of basalt. the average thickness of the continental crust is 25 miles and the average thickness of the oceanic crust is 5 miles.   three types of rock, igneous, sedimentary, and metamorphic, make up the surface of the earth. that's why 3 option is preferable.