Please help:) I'm completing a lab report on investigating cohesion. I have everything completed but I don't understand what my variables would be.

The experiment contains:

Place a clean dry penny on a flat surface.
Fill a small cup of water.
Use a dropper or a pipette to gently drop water onto the penny.
Record the number of drops made before the water spills off the penny.
Dry the penny and repeat steps 1–4. Do three trials.

may someone please explain to me what the independent, dependent, and controlled variables would be? Thank you :)

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.