Which term is described as encapsulating active substances in extremely small capsules?

• A. Smart materials
• B. Thermochromic ink
• C. Nitinol
• D. Micro encapsulation

Answer: (D)

The main idea here is enclosing active substances in very small capsules to protect them and control how they are released. This is exactly what micro encapsulation describes. By packing ingredients into tiny capsules, you can shield sensitive components from moisture, air, or light, mask tastes, and achieve a timed or sustained release as needed. The other terms refer to different concepts: smart materials are about substances that change properties in response to stimuli, thermochromic ink changes color with temperature, and Nitinol is a nickel-titanium alloy with shape memory. None of those describe the act of packaging active ingredients into microscopic capsules, so micro encapsulation is the precise term here.