Reproducing new plants by cells instead of seeds is known as

$v_1$ is the frequency of the series limit of the Lyman series,$v_2$ is the frequency of the first line of the Lyman series,and $v_3$ is the frequency of the series limit of the Balmer series. Then:

For $x \in \mathbb{R}$,the range of $3 \cos (4x - 5) + 4$ lies in the interval

The final product $(III)$ obtained in the reaction sequence:
$CH_3CH_2COOH$ $\xrightarrow{PCl_3} I$ $\xrightarrow[AlCl_3]{C_6H_6} II$ $\xrightarrow[base, heat]{NH_2NH_2} III$ is

Two capacitors $C_1$ and $C_2$ in a circuit are joined as shown in the figure. The potential of point $A$ is $V_1$ and that of $B$ is $V_2$. The potential of point $D$ will be

The point of intersection of the diagonals of a square is at the origin,and the coordinate axes are drawn along the diagonals. If the side length of the square is $a$,which of the following is $NOT$ a vertex of the square?