Which of the following are the main mediators/initiators of type ii hypersensitivity reactions?
antibodies
mast cells
erythrocytes
histamines

Antibodies.

Explanation:

Hypersensitive reaction are intolerable reactions that are mainly occur due to exaggerated immune reactions. Autoimmunity and allergies are mainly produced in the hypersensitivity.

Type II hypersensitive reactions is generally mediated by the IgM or IgG antibodies. Antibodies bind to the target cell that are present as a host cell and result in the Type II hypersensitive reaction.

Thus, the correct answer is option (1).

answer; ///i believe that the correct answer is (a) specialized 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.