A solution with a 0.9% concentration of salt is isotonic to red blood cells so the cells stay the same. Cells
shrivel in hypertonic solutions and swell and burst in hypotonic solutions.
In an experiment testing the effects of various concentrations of salt on red blood cells, which solution would
be predicted to cause the red blood cells to swell and burst?
0.05%
O
0.9%
1.0%
10.0%

0.05%

Explanation:

That's because it's a hypotonic solution. It's solute concentration is lower than than of the cells' contents. So water diffuses in, down the concentration gradient, across a partially permeable membrane via osmosis. This exerts more pressure on the relatively weak cell membrane and cause the cell to swell then burst.

It's less than 0.9% which is the isotonic solution.