Which two classes of rock will form near or at earth’s surface?
a. extrusive igneous and sedimentary
b. sedimentary and intrusive igneous
c. metamorphic and igneous
d. metamorphic and sedimentary

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds

the dna molecules have a negative charge because of the phosphate groups in their sugar-phosphate backbone, so they start moving through the matrix of the gel towards the positive pole. power is turned on and dna fragments migrate through gel (towards the positive electrode).

explanation: