Can someone answer this pls??

75% brown, 25% white

Explanation:

This question involves a single gene coding for color in chickens. The allele for brown color (B) is dominant over the allele for white color (b).

According to this question, a brown rooter with genotype 'BB' was crossed with a white hen (bb). The offsprings in the F1 generation will all possess the 'Bb' genotype and be brown colored. However, if these F1 offsprings are self-mated i.e Bb × Bb, the proportion of F2 offsprings will be 1BB, 2Bb, 1bb.

Since BB, Bb and Bb offsprings are Brown in color and bb is white in color, this means that the expected phenotypic appearance of the F2 offsprings will be:

¾ or 75% brown and ¼ or 25% white

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.