Eric follows a vegetarian eating pattern, and he wants to know whether he needs to take any vitamin and mineral supplements. what would be most important to find out?

It would be most important for Eric to find out his zinc, iron and vitamin B12 (or  riboflavin) levels, and ensure that he is obtaining adequate amounts of these vitamins and minerals through vegetarian sources .

A vegetarian diet is typically low in zinc rich foods, since meat, shell fish and eggs are the most abundant sources of zinc. In order to ensure that he obtains sufficient zinc, Eric should make sure he consumes vegetarian zinc sources such as legumes, lentils, dairy, nuts and seeds on a daily basis.

Since iron and vitamin B12 are also difficult to obtain from vegetarian sources, Eric should consume iron rich foods such as spinach, kale, whole grains, broccoli, legumes,etc., on a daily basis. As for vitamin B12, daily supplementation of 2.4 μg is recommended for vegetarians. Alternatively, riboflavin fortified cereals and grains are also recommended to meet daily riboflavin requirements.

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