Chloramphenicol and erythromycin (broad spectrum antibiotics) are produced by

The binding energy per nucleon versus mass number curve for nuclei is shown in the figure. $W, X, Y$ and $Z$ are four nuclei indicated on the curve. The process that would release energy is

Two strings $A$ and $B$ of lengths $L_A = 80 \ cm$ and $L_B = x \ cm$ respectively are used separately in a sonometer. The ratio of their densities $(d_A / d_B)$ is $0.81$. The diameter of $B$ is one-half that of $A$. If the strings have the same tension and fundamental frequency,the value of $x$ is:

Consider the depicted hydrogen $( H )$ in the hydrocarbons given below. The most acidic hydrogen $( H )$ is

Male gametes are flagellated in

If the straight lines $2x + 3y - 1 = 0$,$x + 2y - 1 = 0$ and $ax + by - 1 = 0$ form a triangle with the orthocentre at the origin,then $(a, b) =$