Selecting resources with reliable credentials and expertise is . A. important for scientific research only
B. important for any information you look up, on any topic
C. not important, everyone’s ideas are equally valid
D. only important when you are looking for medical advice

B. important for any information you look up, on any topic

Explanation:

You want reliable information whenever you are trying to understand something that is unknown to you (not just when you are doing research or need medical advice), and you get reliable information from people with the right credentials and expertise on the given matter.

answer: 21

step-by-step explanation:

divide 630 by 30. 30 goes into 630 21 times

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