Which statement describes the independent variable?
a. it is measured and recorded as data.
b. it is unchanged in the experiment.
c. it is also called the responding variable.
d. it is also called the manipulated variable.

The structure of a dna molecule is best described as a. one long strand of nucleic acids b. two strands of dna nucleotides joined by hydrogen bonds c. two strands of amino acids joined by hydrogen bonds d. one long strand of amino acids