When did the world population reach 6 billion

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.

Sociology is best described as the systematic study of

What was one step that charlemagne took to unite his kingdom? a. he chose a single strong heir to inherit his throne. b. he drove muslim forces out of europe. c. he created and supported schools. d. he declared himself head of the catholic church.