Which dna fingerprinting technique examines the length variation of dna repeat sequences in human dna? a. vntrs (variable tandem repeats) b. pcf (polymerase chain reaction) analysis c. strs (short tandem repeats) d. mtdna (mitochondrial dna) analysis

The answer is; A

Variable Number Tandem Repeats are copies of nucleotide sequences that occur in tandem in individuals' DNA. Different individuals differ in the number of copies of these VNTR hence can be used for DNA fingerprinting. VNTR are usually 20 – 200 base pairs long. Restriction enzymes are used to nick DNA at points flanking the VNTR regions. Individuals will have different lengths hence used to make a match probably with a crime scene sample.

VNTRs (variable tandem repeats) examines the length variation of DNA repeat sequences in human DNA.

desert perennials often survive by remaining dormant during dry periods of the year, then springing to life when water becomes available. most annual desert plants germinate only after heavy seasonal rain, then complete their reproductive cycle very quickly.

affects the water bodies: excessive use of fertilizers causes eutrophication. the fertilizers which are used on plants affect the quality of land on which it is used, further causing erosion of soil. the fertilizers used on plants contain harmful chemical fumes which affect the environment.