Identify the basic amino acid from the following.

If $\int \sec ^2 x \operatorname{cosec}^4 x \, dx = -\frac{1}{3} \cot ^3 x + k \tan x - 2 \cot x + C$, then $k$ is equal to

An engine giving a whistle is moving towards a stationary observer with a speed of $110\,m/s$. What will be the ratio of the frequency of the whistle heard when the engine is approaching and receding from the observer? (The speed of sound is $330\,m/s$.)

Among the following compounds,which one is not responsible for the depletion of the ozone layer?

Which combination of tissues acts together to provide support to the hypocotyl of a seedling?

If $(1+x)^{15}=a_0+a_1 x+\ldots+a_{15} x^{15}$,then $\sum_{r=1}^{15} r \frac{a_r}{a_{r-1}}$ is equal to