Into how many classes are the angiosperms (flowering plants) classified?

The equation $\sqrt{3} \sin x + \cos x = 4$ has

If $A = \begin{bmatrix} \alpha & 0 \\ 1 & 1 \end{bmatrix}$ and $B = \begin{bmatrix} 1 & 0 \\ 5 & 1 \end{bmatrix}$,then the value of $\alpha$ for which $A^2 = B$ is

The point $P$ is equidistant from $A(1, 3)$,$B(-3, 5)$,and $C(5, -1)$. Then $PA =$

Which one of the following gives a straight line for Freundlich adsorption isotherm?

Honey bees also produce beeswax,which finds many uses in industry,such as: