Which statement best defines synthesis in chemistry?

• A. Breaking down a compound into simpler substances
• B. A chemical reaction where electrons are transferred
• C. Combining parts into a whole
• D. A reaction where one element replaces another

Answer: (C)

Synthesis is about building a more complex substance by combining simpler ones. In a synthesis reaction, two or more reactants come together to form a single product, often written as A + B → AB. This idea is seen in examples like forming water from hydrogen and oxygen, or making ammonia from nitrogen and hydrogen. This is different from breaking a compound into simpler substances (decomposition), from reactions where electrons are transferred (redox), or from reactions where an element replaces another in a compound (displacement). So combining parts into a whole best captures what synthesis means.