Quantitative PCR or real-time PCR is a modification of the standard PCR that allows us to monitor the amount of the amplified product after each cycle in real time.
RT-PCR is a modification of standard PCR, which uses reverse transcriptase to transcribe RNA into cDNA, which is then amplified using the standard PCR.
DNA libraries are collections of cloned DNA fragments. There are two main types of DNA libraries, genomic DNA libraries and complementary DNA (cDNA) libraries.