Guinea pig coat color is determined by a single gene. the allele for black coat color is dominant to brown. in a cross between two black-haired guinea pigs, 20 offspring are born. if both parents were heterozygous, probability would predict that approximately how many of the 20 offspring would have brown hair?

In a cross between two black-haired guinea pigs, 20 offspring are born. If both parents were heterozygous, probability would predict that approximately 1 out of 20 offspring would have brown hair

Explanation:

The two parents crossed were heterozygous dominant black coat color, after crossing 75% gives dominant black color coat while 25% gives only brown coat color homozygous

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.