1. Why is cell division essential to living things?
Ifk

As living things grow, some cells die or become damaged and need replacements. Some single-celled organisms use a type of mitosis as their only way to reproduce. In multi-celled organisms, cell division allows individuals to grow and change by expanding the number of total cells in the host.

it allows a living being to replace dead, old or damaged cells, and it also helps some organisms become bigger

i believe it would cause an increase of percipitation, though i could be wrong. so i would say b is the answer.

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.