Proteins generally have widely different structures, whereas nucleic acids have quite similar structures. explain g

Proteins are made up of smaller units called amino acids.There are twenty different amino acids which are joined together in different pattern to form proteins. Further the folding of polypeptide chain give rise to different shapes and structure of proteins. 
Nucleic acids are made up of one kind of monomers call nucleotides. These nucleotides are attached with each other in the form of double strand (DNA) or in single strand form (RNA).

Water vapor

Explanation:

Warm air cooling causes moisture called water vapor which creates water droplets called condensation.