Alexia is testing the effect of adding salt on the conductivity of distilled water. To do this, Alexia took 5 beakers and filled them each up with 50mL of room temperature distilled water. She added 0g of salt to beaker 1, 10g to beaker 2, 20g to beaker 3, 30g to beaker 4 and 40g to beaker 5. She stirred each beaker for 10 seconds and then measured the conductivity. What is the independent (testing) variable?

A Group of answer choices

B the amount of salt in each beaker

C the beaker with no salt

D the conductivity of the beaker

the length of time she stirred the beaker

i think the answer is b.

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.