hooc are carboxyl groups
your r or amino groups are those unique structures which have different atoms in them. your nh2 groups are your hydrogen atoms
A) a column
example: earth alkaline metals
The answer would be "air, wood". Gases have the highest Kinetic energy and least Potential energy. Liquids have the 2nd highest Kinetic energy and 2nd least potential energy and solids have the least kinetic energy and highest potential energy.