A ruler with measurements in the metric system showing millimetres (mm), centimetres (cm) and metres (m).

How strong the muscle in your upper body is (waist and higher).

Causing damage or wear by rubbing, grinding or scraping.

The study of the properties of moving air and the interaction between the air and solid bodies moving through it.

The flow of air moving through or past something, like an airplane or car.

Something that triggers an allergy.

A type of allergic reaction whereby the immune system responds to environmental substances aggressively. Within minutes of exposure to the allergen, there can be rapid airway constriction, a skin reaction and heart rhythms become altered. In very severe cases, it can lead to complete obstruction of the airways and death.

The study of the structure of living things.

Odd results - those which are not in keeping with the rest of the results or which do not follow the trend. They can make the results unreliable.

Pairs of muscles that create movement when one (the prime mover) contracts and the other (the antagonist) relaxes. Examples of antagonistic pairs working are the quadriceps and hamstrings in the leg and the biceps and triceps in the arm.