Which of the following is true about pure substances?
A.
A pure substance has the same chemical properties throughout.
B.
All pure substances are unable to be separated by any means.
C.
A pure substance can only be made up of one kind of atom.
D.
A pure substance can always be separated by physical means.

In what way do investigations build scientific knowledge? the results of investigations lead to questions that cannot be tested. they reflect the opinions and social values of scientists, ensuring valid information. the results of investigations lead to new questions, which lead to new investigations. they are not influenced by the research of earlier scientists, so they are able to address gaps in understanding.i