1. which part of the dna codes for heredity?
a. a ribose sugar
b. a single deoxyribose sugar
c. a sequence of nitrogen bases
d. a sequence of phosphate groups

The correct answer is C a sequence of nitrogen bases.

Explanation:

DNA or deoxy ribonucleic acid is the repository of genetic information.The genetic information is stored within the nitrogen bases of DNA molecule.

     The A,T,G,C are called genetic alphabets of human life.A for adenine,G for guanine,T for thymine and C for cytosine builds the basic structural backbone of DNA along with deoxyribose sugar and phosphate moiety.

    The bases present in DNA are transcribed to forms the bases of mRNA and the concequetive bases of mRNA act as codon that encodes a specific amino acid during the course of translation.

true, i don't really know what you're asking but from the info you provided im guessing the answer is true.

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.