Which of the following is an example of "molecule"?

Explanation

DNA is a very large molecule made of repeating nucleotide units, and each nucleotide contains a sugar, phosphate group, and nitrogenous base. A chloroplast and nerve cell are cellular structures, while hydrogen is an element rather than a named molecule in this context. Students may choose hydrogen because hydrogen gas exists as H2 molecules, but the option normally refers to the element.