Caffeine is an inhibitor of phosphodiesterase. therefore, the cells of a person who has recently consumed coffee would have increased levels of
a) phosphorylated proteins
b) camp
c) adenylyl cyclase
d) activated g proteins

B) cAMP

Explanation:

Phosphodiesterase is an enzyme that breaks a phosphodiester bond, for example in molecules such as cAMP and cGMP. So, phosphodiestarases are  are regulators of signal transduction: regulate the duration of signaling pathway.

Caffeine is  central-nervous-system stimulant and the mechanisms of its action usually are: mobilization of intracellular calcium or inhibition of specific phosphodiesterases.

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.

cells spend most of their time in interphase