Gene expression is often assayed by measuring the level of mrna produced from a gene. if one is interested in knowing the amount of a final active gene product, a potential problem of this method is that it ignores the possibility of ) chromatin condensation controlb) transcriptional control c) alternative splicing d) translational control

D) translational control

Explanation:

Translational regulation is the last step of gene regulation and it refers to the control of the levels of protein that synthesized from the mRNA. It directly regulates  protein concentration. The phases of translation that are under the control are: ribosome recruitment on the first, initiation codon;  peptide elongation; termination;  ribosome biogenesis.

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