Natural selection can lead to (a) stabilisation (b) genetic drift (c) directional change (d) disruption Choose the correct answer from the options given below :

A protein undergoes reversible thermal denaturation from its initial state N to denatured state D according to $N \rightleftharpoons D$. At $60^{\circ}C$, the concentrations of both N and D are equal at equilibrium, and the standard enthalpy change of denaturation is $666~kJ~mol^{-1}$. The standard entropy change ($\Delta S^{\circ}$ in $kJ~K^{-1}~mol^{-1}$) of the protein upon denaturation at $60^{\circ}C$ is closest to

Consider three media P, Q and R with refractive indices 1, 1.25, and 1.5 respectively. The medium Q having a thickness of 5 cm is placed between extended media P and R as shown in the figure. An object O is placed at the centre of medium Q. If viewed from medium P near the normal direction, the apparent depth of O is $h_1$. For similar observation from medium R, the apparent depth is $h_2$. The value of $|h_{1}-h_{2}|$, in cm, is: [Image Placeholder]

An electromagnetic wave travelling in a lossless dielectric medium having a dielectric constant, $\epsilon_{r}=9$, has the electric field, $E_{x}=E_{0} \sin(kz-2\pi\times10^{6}t)Vm^{-1}$ where $E_{0}$ is the amplitude and k is the wave vector. Among the following options, the incorrect choice is

$2A\rightarrow B$ is a zero-order reaction, where $k=1.0~mol~L^{-1}min^{-1}$. If the initial concentration of A is 2 M, then the time taken to complete 75% of the reaction will be