Science glossary

• DNA (short for deoxyribonucleic acid, pronounced de-OX-e-RI-bo-nu-clay-ic AS-id). The famous basic strands of life. DNA carries coded information about what characteristics living things will pass on, in its unique ladder shape.

• Chromosomes (pronounced KROE-ma-somes). Very long, continuous pieces of DNA. They can contain hundreds of genes. Human cells have 23 pairs of chromosomes.

•Heredity (heh-RED-i-tee). Passing on biological traits or characteristics from parents to offspring through genes.

• Gene (JEAN). The basic unit of heredity. Traits, such as whether a watermelon has seeds, are determined by the information carried in genes.