All living organisms use 20 amino acids to build their proteins, reflecting a common ancestry. What makes the amino acids different from one another?

The answer to your question is below

Explanation:

Amino acids are organic molecules which are the bricks of proteins. The order of amino acids determines the different kinds of proteins that they can form.

As their name mentions, all amino acids have an amine group and a carboxylic acid group. We can differentiate them because of the group R of the central carbon.

See the picture below.

R can be    -CH₃ , - COOH, -CH₂CH₃, etc, R is different for each amino acid.

indicate valleys, hills, steepness and gentleness of slopes.

explanation:

contour lines on a map indicate elevation, or depth. numeric notations on contour lines refer to the level of elevation, or height about sea level.