The answer is D
Consulting their chemistry teacher and other students in class would not be in depth enough, so A and B are not the answers.
While consulting a chemistry textbook will be useful, the scientific journal is not the best choice.
However, the chemistry textbook would be great, and the periodic table of elements os necessary if they are doing a study about it so the best answer would be D.
Hope this helps!
Answer:
solids are more tightly packed together (the molecules) than liquid or gas so it allows it to travel through vetter/faster
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