Explain in complete sentences why lettuce or spinach in water becomes firm and crisp by cell membranes?

Lettuce and spinach has a semi permeable membrane
since it's put into water, which water has a higher water potential than the leaf cells, water molecules will pass from the water to the cells through the membrane by osmosis . this leads the cells to be turgid and therefore the lettuce and spinach becomes firm

Cells of an organism tell each other when predators are near.