Membrane proteins are among the most important proteins biologically because they allow the cells to communicate with their environments. these membrane proteins are responsible for all but which process?
a) triggering ion channels
b) identifying foreign cells
c) regulating intake of oxygen
d) activating growth hormone reactions

C)regulating intake of oxygen  

Explanation:

Plasma membrane proteins perform a variety of functions: they act preferentially on transport mechanisms, organizing true tunnels that allow substances to pass into and out of the cell, function as membrane receptors, and receive signals from substances that carry some message to the cell, favor adhesion of adjacent cells in a tissue, serve as anchor point for the cytoskeleton. In addition, these proteins trigger ion channels, identify foreign cells in the body, activate growth hormone reactions, but do not regulate oxygen intake regulation.

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.

air enters through the nose, moves through the nasal cavity, the pharynx, the larynx, enters the trachea, moves through the bronchi andbronchioles till the alveoli.