Imagine a different system in which toads had a wide range of variation in color. In some ponds, most of the toads are light in color. In other ponds, the average color is fairly dark. From the options below, select which represent TESTABLE hypotheses that could explain this difference in coloration. A. A predator that is present in some ponds prefers one color to the other. B. Female toads in some ponds prefer darker toads, while females in another pond prefer lighter toads. C. Toad color is determined by food quality, which varies pond to pond. D. Toads can change their color, based on their stress level.

the answer is; comparing the frequency of collisions with and without the device

this makes the anti-collision system an independent variable and the collisions a dependent variable. if there are fewer collisions with an anti-collision system that without, then it can be stated that the system is a success. essentially, collisions under an anti-collision system are compared with the frequency of collisions by cars with the human drivers.

the answer is c.) there is a warm front in region a and a stationary front in region 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.