What describes diffusion?

What describes diffusion?

• A. Isotonic Solution
• B. Diffusion
• C. Hypertonic Solution
• D. Endocytosis

Answer: (B)

Diffusion is the net movement of molecules from an area of higher concentration to an area of lower concentration as a result of their random motion, and it happens without using cellular energy. This means substances spread out until they are evenly distributed, like perfume dispersing in a room or dye gradually diffusing through water. In cells, diffusion allows small, nonpolar or lipid-soluble molecules to cross membranes down their concentration gradient. The other terms describe different ideas: an isotonic solution has equal solute concentrations on both sides with no net water movement, a hypertonic solution has higher outside solute concentration causing water to leave, and endocytosis is a energy-requiring process where the cell engulfs material in a vesicle. Diffusion best matches the concept of substances spreading from high to low concentration without energy input.

Diffusion is the net movement of molecules from an area of higher concentration to an area of lower concentration as a result of their random motion, and it happens without using cellular energy. This means substances spread out until they are evenly distributed, like perfume dispersing in a room or dye gradually diffusing through water. In cells, diffusion allows small, nonpolar or lipid-soluble molecules to cross membranes down their concentration gradient. The other terms describe different ideas: an isotonic solution has equal solute concentrations on both sides with no net water movement, a hypertonic solution has higher outside solute concentration causing water to leave, and endocytosis is a energy-requiring process where the cell engulfs material in a vesicle. Diffusion best matches the concept of substances spreading from high to low concentration without energy input.