Red blood cells were found to have burst open after being placed in distill for an hour. This phenomenon is known as

Step 1: Analyze the question Red blood cells are placed in distilled water (the question says "distill", meaning distilled water). They burst open. We need the term for this.

Step 2: Explain the concept Distilled water is pure water, so it is hypotonic compared with the fluid inside red blood cells. By osmosis, water moves from the area of higher water potential (the distilled water) into the cell, which has lower water potential.

Animal cells like red blood cells have no cell wall, so they cannot resist the extra water pressure. They swell and eventually burst. This bursting of red blood cells is called haemolysis (haem = blood, lysis = breaking or bursting).

Step 3: Check each option

• A. Plasmolysis: This is the shrinking of a plant cell's protoplasm away from the cell wall in a hypertonic solution. It is the opposite situation, so it is wrong.
• B. Diffusion: This is the general movement of particles from high to low concentration. It does not describe cells bursting, so it is wrong.
• C. Haemolysis: This is the bursting of red blood cells, usually from water entering by osmosis. It is correct.
• D. Wilting: This is the drooping of plants from water loss, so it is wrong.

Step 4: Answer The correct answer is C. haemolysis.

Tip: Break the word into parts: haemo = blood and lysis = burst. Also remember:

• Animal cell in hypotonic solution → haemolysis (bursts)
• Plant cell in hypotonic solution → becomes turgid (the cell wall stops it bursting)
• Plant cell in hypertonic solution → plasmolysis