Final answer:
Genomic libraries and cDNA libraries differ in terms of the DNA fragments they represent and their focus. Genomic libraries contain all possible fragments of a genome, while cDNA libraries only contain DNA from expressed genes. Genomic libraries can be used for studying the entire genome, while cDNA libraries focus on expressed genes.
Step-by-step explanation:
Genomic libraries are made by cloning genomic fragments from an organism into plasmid vectors or bacteriophage, while cDNA libraries are generated using mRNA from a cell. Genomic libraries represent all possible fragments of a genome, while cDNA libraries contain only DNA from expressed genes in a cell. Genomic libraries can be used to study the sequence and structure of the entire genome, while cDNA libraries focus on the expressed genes in the cell.