List the main uses of bacteria

the production of foods like yoghurt and cheese

. agriculture and fertilisation

Also genetic engineering

check for the pregnancy rating of drug. if its class c or d see if other alternatives

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