The inherited traits of an organism are controlled by?

Step 1: Analyze the question The question asks what controls the inherited traits (hereditary characteristics) of an organism. This is really a genetics/biology concept, even though it appears under Chemistry here.

Step 2: Explain the concept Inherited traits are passed from parents to offspring through genes. Genes are specific segments of DNA (deoxyribonucleic acid), found mainly in the chromosomes in the nucleus. DNA stores the genetic information (the code) that determines traits such as eye colour, blood group and height.

Step 3: Evaluate each option

• A. RNA molecules: RNA helps carry out the instructions in DNA (for example, mRNA carries the code and tRNA brings amino acids during protein synthesis). It is not the main carrier of inheritance in most organisms (only in some viruses).
• B. Nucleotides: These are only the building blocks (a sugar, a phosphate and a nitrogenous base) that make up DNA and RNA. A single nucleotide does not hold the hereditary information. The sequence of many nucleotides in DNA does.
• C. DNA molecules: DNA contains the genes, which are the units of heredity. It is replicated and passed from one generation to the next. ✔
• D. Enzymes: These are proteins that speed up reactions. They are produced under the instruction of genes, so they do not control heredity.

Step 4: Answer The correct answer is C. DNA molecules.

Tip: Remember "DNA = Data storage for heredity". DNA holds the information, RNA works as the messenger, and enzymes are the workers. If a question asks what carries or controls inheritance, think DNA/genes/chromosomes.