What enables dna to have so many variations with only 4 chemicals?

Different combinations between these four set of chemicals

Explanation:

There can be billions of combinations between the four chemicals of DNA. The four set of chemicals i.e nucleotide (generally referred to as bases) namely -  

A- Adenine  

T- Thymine  

C - Cytosine  

G - Guanine

These nucleotide form codon i.e set of three nucleotide and form chain structure which can be long up to any extent.  

Codon example - ATC TGA

Thus, variation in combination of four nucleotide and ability to form long chain of codon allows DNA to have several forms and variations

economic impact of malaria is estimated to cost africa $12 billion every year. this figure factors in costs of health care, absenteeism, days lost in education, decreased productivity due to brain damage from cerebral malaria, and loss of investment and tourism.

wait any answer choices plz