When people get their hair chemically straightened, one chemical is put on the hair to break the disulfide bond that give the hair strands their shape and a second chemical is used to reform the disulfide bonds to hold the hair in a new position. what level of protein is affected by these processes. why doesnt the hair stay straight forever after treatment

Chemically straightening hair changes the shape of disulfide bonds, which alpha keratin protein; this is the second protein structure. However, as the hair continues to grow out, this keratin protein grows with it, thus outlasting the effects of the chemicals which change the shape of the protein.

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.

more words for this could be abiotic and biotic

abiotic: living organisms within an ecosystem

biotic: non-living organisms within an ecosystem