AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.
Bio-catalysts used by organisms to break down complex substances into simpler ones are called enzymes.
The passage directly states: "To achieve this, organisms use bio-catalysts called enzymes." This is a straightforward one-word/one-line answer. Examiners award the mark for the term "enzymes." No elaboration is needed for 1 mark.
Source: Chapter 5, Section 5.2 Nutrition