Spoilage of oil can be detected by which fatty acid : -

A mutant strain of T4 – Bacteriophage, R-II, fails to lyse the E-Coli but when two strains RIIX and R-IIY are mixed then they lyse the E.Coli. What may be the possible reason : -

Salmonella is related with : -

Which of the following cut the DNA from specific places ?