Which semi-dwarf variety of plant was developed by Nobel laureate Norman $E$. Borlaug?

In the electrolytic extraction of $Al$,molten cryolite is used because it .......

Which of the following is an industrial fuel?

The coefficient of $x^k$ in the expansion of $\frac{1-2x-x^2}{e^{-x}}$ is

It is now possible to breed plants and animals with desired characters through

Two particles $A$ and $B$ of masses $m$ and $2m$ are suspended from massless springs of force constants $K_1$ and $K_2$. During their oscillation,if their maximum velocities are equal,then the ratio of amplitudes of $A$ and $B$ is