Genetic drift and natural selection only take place if there is

Genetic variation  

Explanation:

Drift and natural selection are natural phenomena that occur when there exists genetic variation. In the first case (drift), the consequence will be the decrease in the genetic diversity, while natural selection will change the allele frequencies in order to favor adaptive genetic differentiation

carbohydrates: (starches and sugars) composed of carbon, hydrogen, and oxygen.

lipids: (fats, oils, and waxes) are made of carbon and hydrogen atoms.

nucleic acids: contain hydrogen, oxygen, nitrogen, carbon, and phosphorus. they are polymers of nucleotides. a nucleotide has three parts, a 5-carbon sugar, a phosphate     (-po⬇️4) group, and a nitrogenous base.

proteins: made up of nitrogen, carbon, hydrogen, and oxygen. they are polymers of amino acids.