Provide at least three reasons why friction is needed.

Although you normally hear about trying to reduce or eliminate friction, it actually has some important uses.

Since friction is a resistance force that slows down or prevents motion, it is necessary in many applications where you might want to hold items or do things and prevent slipping or sliding. In those cases, there is an advantage of having friction.

Quite often uses of frction can be seen from how things would be without friction. Without friction, you would not be able to walk, drive a car, or hold objects. Pens and pencils would not work.

Explanation:

Friction allows people and objects to move. It provides traction for an object to start moving or change direction. It can also give people a better grip on objects. Finally, friction keeps objects in place when they are set down.

Explanation:

Sample Response

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.