Identify the control group the experimental group the independent variable and the dependent variable. A new sunscreen has been
developed that is supposed to be
more effective at preventing
sunburn. 30 participants spray
one arm with
the new formula, and spray the
other arm with the leading
formula. After 4 hours in the sun,
their skin is evaluated for any
redness.

the controlled group is the leading brand, the experimental group is the new formula, the independent variable is the sun, and the dependent variable is the skin.

Explanation:

I hope this is correct and helps. :)

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.