Through the process of gene expression different cell types use the information in different genes to make different

any abiotic or biotic factor in an ecosystem that causes a population's size to slow or decrease is a limiting factor.

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

answer: dna

because all cells have genes