Clouds because they cause rain. Gravity could because it plays a part in what direction and when weather occurs.<span />
The correct answer is: A. by the sequence of nitrogenous bases
The genetic code is the set of rules which is represented by the specific order of nucleotide bases. It is used by cells to translate information encoded within genetic material (DNA) into proteins. The genetic code consists of nucleotide triplets-codons, specify which amino acid will be added next during protein synthesis.
I believe its D. An experiment that reveals a new step in a metabolic pathway.
Hope this helps! ;)