Which characteristic of living organisms ensures that the population size of each species remains limited?

Match the following columns:

Column-$I$	Column-$II$
$A$. Christmas tree	$i$. Bennettites
$B$. Fossil plant	$ii$. Cycas
$C$. Ornamental plant	$iii$. Araucaria
$D$. Tallest tree	$iv$. Sequoia
	$v$. Thuja

Find out the major product of the following reaction:
$2 \text{ mole } CH_2=CH-CH_2Br \xrightarrow{Mg, T.H.F}$

Which one of the following pairs of reactants does not form oxygen when they react with each other?

Two concentric coils each of radius equal to $2\pi \, cm$ are placed at right angles to each other. $3\, A$ and $4\, A$ are the currents flowing in each coil respectively. The magnetic induction in $Wb/m^2$ at the centre of the coils will be $(\mu_0 = 4\pi \times 10^{-7} \, Wb/A \cdot m)$.

$A$ die is thrown $10$ times. The probability that an odd number will come up at least one time is: