How does a sedimentary rock become stratified?

In dna, only the_ varies from one nucleotide to another. base phosphate sugar amino acid

(amoeba sisters video recap: pedigrees and need

What do isotopes of uranium have the same number of? what do they have a different number of? a) same number of protons; different number of electrons b) same number of protons; different number of neutrons c) same number of electrons; different number of protons d) same number of neutrons; different number of protons