What is a hypertonic, hypotonic, and isotonic solution?

Explanation:

If a cell is placed in a hypertonic solution, water will leave the cell, and the cell will shrink. In an isotonic environment, the relative concentrations of solute and water are equal on both sides of the membrane.  When a cell is placed in a hypotonic environment, water will enter the cell, and the cell will swell.

your answer is "the 1950's"

here is the answer

water, ice, acids, salts, plants, animals, and changes in temperature are all agents of weathering. weathering is the breaking down or dissolving of rocks and minerals on earths surface. once a rock has been broken down, a process called erosion transports the bits of rock and minerals away.