Heat is always transferred from warmer to cooler environments and conduction is the simplest way this transfer can occur. It is accomplished through direct contact between materials and materials like metals that transfer heat efficiently are called conductors while those that conduct heat poorly, such as plastic, are called insulators.

The broadest classification of life splits all organisms into three groups called domains. The three domains of life are bacteria, archaea and eukaryota.

An element is matter than cannot be separated into different types of matter by ordinary chemical methods.

Force is applied to change an object's speed or direction of motion.

Food is mixed with gastric acid and pepsin in the stomach to help break down protein.