Which of the following statements describes what happens to a molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction

In a redox reaction, a reducing agent will donate electrons to another chemical species and then it becomes oxidized.

Explanation:

A redox or oxidation-reduction reaction is a chemical reaction where exchange of electron(s) happen between two chemical species (molecule, atom or ion). In this reaction, one chemical species act as an oxidizing agent while another will be a reducing agent.

An example of redox reaction is given in the attachment.

In a redox reaction, the oxidation number of a reducing agent will be increased,  whereas oxidizing agent will be reduced.  

your answer is "the 1950's"

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.