Molecular Basis of Inheritance

Distinguish between retrotransposons and DNA transposons
Distance between two successive base pairs in DNA is
Study the diagram given below and answer the questions that follow :A typical agarose gel electerophoresis showing migration of DNA fragments.
Lac operon model was proposed by 
The sequence of events mentioned below are symbolised by alphabets. Choose the correct answer where the alphabets are matched with the processes.
$$RNA \xrightarrow{A} DNA \xrightarrow{B} DNA \xrightarrow{C} mRNA \xrightarrow{D} Polypeptide$$