Why is the probability of a reaction with molecularity higher than $3$ very rare?

$[A]_0 / \text{mol } L^{-1}$	$t_{1/2} / \text{min}$
$0.100$	$200$
$0.025$	$100$

For a given reaction $R \rightarrow P$,$t_{1/2}$ is related to $[A]_0$ as given in the table:
Given: $\log 2 = 0.30$
Which of the following is true?
$A.$ The order of the reaction is $1/2$.
$B.$ If $[A]_0$ is $1 \text{ M}$,then $t_{1/2}$ is $200 \sqrt{10} \text{ min}$.
$C.$ The order of the reaction changes to $1$ if the concentration of reactant changes from $0.100 \text{ M}$ to $0.500 \text{ M}$.
$D.$ $t_{1/2}$ is $800 \text{ min}$ for $[A]_0 = 1.6 \text{ M}$.
Choose the correct answer from the options given below:

The rate of reaction $A + B \rightarrow P$ is $4 \times 10^{-2} \text{ mol dm}^{-3} \text{ s}^{-1}$. When $[A] = 0.2 \text{ mol dm}^{-3}$ and $[B] = 0.1 \text{ mol dm}^{-3}$, what is the rate constant of the reaction, if it is first order with respect to $A$ and second order with respect to $B$?

The order of a reaction which has the rate expression $\frac{dc}{dt} = K[E]^{3/2}[D]^{3/2}$ is

For the reaction $N_2O_5 \rightarrow 2NO_2 + \frac{1}{2} O_2$,given that:
$-\frac{d[N_2O_5]}{dt} = K_1[N_2O_5]$,
$\frac{d[NO_2]}{dt} = K_2[N_2O_5]$,
$\frac{d[O_2]}{dt} = K_3[N_2O_5]$
What is the relationship between $K_1$,$K_2$,and $K_3$?

For the reaction $A + B \xrightarrow{K} C$,identify the incorrect order of reaction indicated against the rate expression.