In 1937,a man employed to lay water pipes in Croyden, England, was found to be the source of severe epidemic of typhoid fever. T heman , an asymptomatic carrier of SALMONELLA ENTERICA serotype Typhi, the bacterium that causes typhoi, habitually urinated at his job site. In this process, he contaminated the town's water supply with bacteria from his bladder. Over 300 cases of typhoid fever developed ,and 43 people died before man was identified as the carrier.

a. How do you think health officials were able to indentify the source of this typhoid epidemic?
b. Given that antibiotics were not generally avalible in 1937,how could health officials end the epidemic short of removing the man from the job site

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.

the answer is c. it will give up it's valence electron to the other atom.