And you! btw this is a science question, but i couldn't find a science category ; )

what does it mean to have a well-defined question to study?
a. the question can be answered yes or no.
b. the question can be tested in one experiment.
c. the question is about how a scientific term should be defined.
d. the question is something that everyone is really interested in.

24-karat gold is considered to be pure gold. 18-karat gold is considered to be about 75% gold. what is 18-karat gold considered a mixture rather than a pure substance? a) it has a variable composition of other elements and minerals. b) its color is different than pure gold. c) the gold atoms are not arranged in a repeating pattern. d) it can be melted and transformed into a different substance.

What was the main motivation for the early populists

What makes water a renewable source