Which scientists conducted in-depth research in the field of plant classification?

The solution of $\cos y + (x \sin y - 1) \frac{dy}{dx} = 0$ is

The number of ways that $8$ beads of different colours can be strung as a necklace is

Which of the following statements is incorrect?

The halide of a metal $MX$ crystallizes in a $ccp$ structure ($NaCl$ type). If all the atoms situated on one of the tetrad axes are removed,what will be the simplest molecular formula of the halide?

$A$ particle is released from height $S$ from the surface of the Earth. At a certain height its kinetic energy is three times its potential energy. The height from the surface of the Earth and the speed of the particle at that instant are respectively: