It is necessary to develop alternative sources of energy because. scientists are uncertain of how long the resources will last.
scientists are certain of how long the resources will last.
only a select group of people have information on our resources.
scientists have estimated how long the resources will last.

*tilts head* sounds more like a statement

i had this on my unit activity, i can you if you are a plato student. are you a plato student?

r just means there's a number of carbon in teh chain. for example rcooh means that after x number of carbon, the chain ends with cooh.

explanation:

in cartography, a contour line (often just called a "contour") joins points of equal elevation (height) above a given level, such as mean sea level. a contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys and hills, and the steepness or gentleness of slopes.

explanation: