Please help it is very needed

probably c i'm not too good with chemistry however i can tell u how  got it

Explanation: 27/13Al+1/0

or

simplify 27lA>13  which = 1>0

in my terms 1/0n the answer is c

btw no worries i tend to add a lot of people on and when i send them a request i try to help them the best i can regardless of the trouble it takes, i'm not some crazy weirdo with a crazy crush, that's what all my friends thought, but nah not true i just like to help anyways.. uhm lemme stop typing

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:

in 1783 cavendish was working with his hydrogen gas and found that when he burned it and condensed the vapor it was water. this was very significant since it disproved the greek theory of elements completely since water was not a simple substance but the product of two gases. it was lavoisier who hearing of the experiment gave cavendish's gas the name hydrogen ("water-producer") and added that hydrogen burned by combining with oxygen and that water was a hydrogen-oxygen combination.

explanation: