Which of the following is $NOT$ included in the class of Bryophyta as classified by Rothmaler?

Which of the following is not correct?

The number $\log_{2} 7$ is:

The number of arrangements of the letters of the word $PALANHAR$ in which no two vowels are together and exactly two vowels are at odd places,is

$S$ and $T$ are the foci of an ellipse and $B$ is an end point of the minor axis. If $\triangle STB$ is an equilateral triangle, then the eccentricity of the ellipse is:

The equation $\frac{1}{r} = \frac{1}{8} + \frac{3}{8} \cos \theta$ represents