Which classification system was proposed by $R.H. Whittaker$?

In tissue culture experiments,leaf mesophyll cells are put in a culture medium to form callus. This phenomenon may be called as:

All the diodes are ideal. The current flowing in the $2 \, \Omega$ resistor connected between the diodes $D_1$ and $D_2$ is .......... $A$

Water vapour comes out from the plant leaf through the stomatal opening. Through the same stomatal opening,carbon dioxide diffuses into the plant during photosynthesis. Reason out the above statements using one of the following options:

If $(1, a)$ and $(b, 2)$ are conjugate points with respect to the circle $x^2+y^2=25$,then $4a+2b$ is equal to

All the pairs $(x, y)$ that satisfy the inequality $2^{\sqrt{\sin^2 x - 2\sin x + 5}} \cdot \frac{1}{4^{\sin^2 y}} \leq 1$ also satisfy the equation: