What do bacteria have surrounding their cell membrane

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.

Rank the following from most to least devasting: ordovician,permaian,cretaceous, pleistocene

In the spring of 1989, thousands of protesters gathered in tiananmen square in beijing, china. they rallied around a plaster statue that resembled the statue of liberty which they called “the goddess of democracy.” these protestors were seeking a) united states assistance in gaining better health care. b) economic reforms which would allow more chinese exports. c) the boycott of the future olympic games scheduled for beijing. d) political reforms to allow more freedom of speech and political representation.