Answer:
The correct option is : cells containing empty plasmid vectors
Explanation:
The blue-white screen is a technique which involves the rapid identification of the recombinant bacteria in a vector-based molecular cloning experiment. In this method, a DNA ligated vector is inserted in a host cell which is viable for transformation and grown in presence of X-gal.
The cells that are transformed with the vectors having the recombinant DNA produce the white colonies. Whereas, the cells transformed with empty vector i.e. the non-recombinant plasmids, produce the blue colonies.
Nutrients Pollution
Surface Water Pollution
Oxygen Pollution
The investigators could distinguish human hair from animal hair by the patter of pigmentation and by the medullary index.
The pigmentation in human hairs is denser toward the cuticle, whereas in animal hair is denser toward the medulla. Human hairs are usually one colour throughout the whole length, while animal hairs may change colour suddenly.
The medulla in humans is thinner than in animals: the medullary index for human hairs is 0.33 or less; the medullary index for animal hairs is 0.5 or more.
