Perlon is

In the given columns, column $I$ contains the terms and column $II$ contains their descriptions. Select the correct match from the options given below.

Column $I$	Column $II$
$A$. Growth	$I$. Production of offspring.
$B$. Reproduction	$II$. Composed of one or more cells.
$C$. Metabolism	$III$. Increase in mass and increase in number of individuals.
$D$. Cellular organization	$IV$. Sum total of all chemical reactions occurring in the body.

Aluminium reacts with $NaOH$ and forms compound '$X$'. If the coordination number of aluminium in '$X$' is $6$,the correct formula of $X$ is

For the transistor circuit shown below,if $\beta = 100$ and the voltage drop between the emitter and base is $0.7\ V$,then the value of $V_{CE}$ will be.....$V$.

The ratio between kinetic energy and the total energy of the electrons of a hydrogen atom according to Bohr's model is

Which is the most important cereal crop of temperate regions?