The polymer having an amide linkage is

The solution of the differential equation $\frac{dy}{dx} - 2y \tan 2x = e^x \sec 2x$ is

The velocities of two particles $A$ and $B$ are $0.05 \ ms^{-1}$ and $0.02 \ ms^{-1}$ respectively. The mass of $B$ is five times the mass of $A$. The ratio of their de-Broglie's wavelength is

In a single slit diffraction experiment, the first minimum for red light $(\lambda = 660 \, nm)$ coincides with the first secondary maximum of some other wavelength $\lambda'$. The value of $\lambda'$ is ...... $\mathring{A}$.

Assertion : Galvanised iron does not rust.
Reason : Zinc has a more negative electrode potential than iron.

Which one of the following is not a second messenger in hormone action?