Salt solution vs Distilled Water

$\color{#3D99F6} \text{Using 0.9 \% NaCl Solution}$ :

The biologist was successful in conducting her experiment. That means the concentration in out of the cell are equal so there is no net movement of water and the cells are in their usual size. so, we can conclude that $\color{#20A900} \text{the concentration inside cell is 0.9}$ .

$\color{#3D99F6} \text{Using Distilled Water}$ :

Distilled water is neutral. So, it concentration is 0. Now, if the same cell is kept in distilled water it means, the concentration in the surroundings of the cell is less than that in cell . So, water moves into the cell from surroundings due to osmosis . Therefore, after some time $\color{#20A900} \text{as more water will come inside the cell and enlarges it to some extent after which it bursts.}$

The below picture tells about the condition of cell when kept in different solutions.

Water moves in and out of the animal cell through the semi-permeable membrane through a process called osmosis . Osmosis is the spontaneous net movement of solvent molecules (in this case, water) through a selectively permeable membrane into a region of higher solute concentration, in the direction that tends to equalize the solute concentrations on the two sides.

If distilled water is used, which has zero solute concentration, there would be a continuous net movement of water into the cells and the cells would burst . A 0.9% saline (NaCl) solution is used to provide the osmotic pressure or the solute concentration necessary to prevent the excessive movement of water into the cells.

By osmosis, water from outside the cells would move into the cells, causing them to burst.

Osmosis moves from most pure to least pure. Due to the distilled water having no other molecules in it other than water, thus the water goes into the cell causeing it to inflate then burst after a certain amount of time.

This is an osmosis question. The entire concept revolves around the concentration of solutes dissolved in solutions. Water molecules will move from an area of high concentration to an area of low concentration. Water can pass, unaided(passively), through a semi-permeable membrane, as is an animal cell membrane. Solutes, are dissolved particles, usually, in living animals, composed of salts, minerals, proteins and sugars, atoms and molecules. Without dissolved solutes the water solution could be 100% composed of water molecules. Compare this to a solution with some solutes dissolved in it. Solutes have mass and occupy space. The more solutes dissolved between the water molecules, the more space the solutes occupy and the less space the water molecules occupy. If you place a semi-permeable membrane between both solutions the area of low concentration of water is the one with the higher concentration of dissolved solutes. The area with the highest concentration of water is the solution with no solutes dissolved within it. So, if water will naturally desire to move from an area of high concentration to an area of low concentration, which direction will it flow across the semipermeable membrane? The pure water is on the left side of the membrane and the dissolved solutes solution is on the right side of the membrane? Remember, the solutes cannot passively move across the semipermeable membrane, only the water can. Correct, left to right!!🙋

Simply, osmotic pressure. Water goes through highly concentrated place. In NaCl, Concentration is quiet similar. But distilled water, however, water moves into cell, stir up the burst of it.