What is the effect of external pressure on the osmotic pressure $(OP)$ of a solution?

$2.5 \, g$ of protein containing only glycine $(C_2H_5NO_2)$ is dissolved in water to make $500 \, mL$ of solution. The osmotic pressure of this solution at $300 \, K$ is found to be $5.03 \times 10^{-3} \, bar$. The total number of glycine units present in the protein is $....$
(Given : $R = 0.083 \, L \, bar \, K^{-1} \, mol^{-1}$)

For a very dilute solution of an electrolyte,which of the following relations is correct? (Assume other parameters are constant)

At a certain temperature,the value of the slope of the plot of osmotic pressure $(\pi)$ against concentration $(C \text{ in } mol \ L^{-1})$ of a certain polymer solution is $291 \ R.$ The temperature at which osmotic pressure is measured is: $(R \text{ is the gas constant})$

Which one of the following is an isotonic pair of solutions?

Assertion $(A)$: Blood cells collapse when suspended in saline water.
Reason $(R)$: Cell membrane dissolves in saline water.