At which population growth rate is the coal supply on earth expected to last the longest
a. high growth
b. average growth
c. no growth
d. low growth

C. no growth

Explanation:

Coal is fossil fuel, its supply is limited and it takes millions of years to form. We humans use a lot of coal to meet our energy needs. The higher the population growth, the greater the need for energy and more coal will be taken from the earth's coal supply. One day this supply will run out as the population keeps growing.

For coal supplies available on earth to last longer would require no population growth, so our energy needs would not grow as it would be equal to the size of the population we now have.

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.