A genome-wide association study involves searching the genomes of many people in order to find genetic variations associated with common diseases such as cancer, asthma, and diabetes. These studies are possible because of computer databases that allow researchers to compare the genomes of people who do not have a particular condition with the genomes of people who have the condition. In order to do this type of testing, researchers need blood samples or cheek swabs from people. Obtaining these samples is necessary because blood and cheek cells contain___________
A. plasma and platelets
B. a complete set of DNA
C. essential proteins and amino acids
D. a large number of neutrophils