As a student jumps over a hurdle, she loses contact with the ground and moves upward. She returns to the ground because unbalanced forces cause a change in the — A mass of the student B height of the student’s jump C gravitational pull on the student D speed and direction of the student

I believe its D speed and direction of the student

Explanation:

Unbalanced forces change an objects motion called acceleration

Acceleration is the change in speed or direction of an object

nucleic acid molecules are incredibly complex, containing the code that guarantees the four different nucleotide units comprise dna, the nucleic acid of interest to the genealogist. and one of four nitrogen-containing molecules called nucleotides

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