Genes that are involved in turning on or off the transcription of a set of structural genes are called

$A$ converging beam of rays is incident on a diverging lens. Having passed through the lens,the rays intersect at a point $15 \, cm$ from the lens on the opposite side. If the lens is removed,the point where the rays meet will move $5 \, cm$ closer to the lens. The focal length of the lens is.....$cm$

Which cell organelle can be identified by Sudan Black?

Considering only the principal values of inverse functions,the set $A = \{x \geq 0, \tan^{-1}(2x) + \tan^{-1}(3x) = \frac{\pi}{4}\}$

In a reaction,$A + B \rightleftharpoons C + D$,$40 \%$ of $B$ has reacted at equilibrium,when $1 \ mole$ of $A$ was heated with $1 \ mole$ of $B$ in a $10 \ L$ closed vessel. The value of $K_C$ is

If the pair of straight lines given by $Ax^2+2Hxy+By^2=0$ $(H^2 > AB)$ forms an equilateral triangle with the line $ax+by+c=0$,then $(A+3B)(3A+B)$ is equal to: