What is the purpose of a dichotomous key of the
sort you might find in a field guide? Check all that
apply.
to determine what sort of field you are located
in
to identify species in the wild
to measure the magnetic or electric field of an
organism
to compare species to each other

it's the cell cycle, but cytokines is when the cell divides.

theres 3 stages interphase,mitosis,and cytokines.

interphase prepares the cell for division.

mitosis is the process of dividing the cell,it has 4 parts interphase,anaphase,metaphase,and telophase.

lastly there's cytokines,that's when the cell divides into 2 daughter cells

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.

i think the answer is a.keratin is the pigment responsible for skin color.