| Questions | 5 | 
| Topics | Carbohydrates, Kingdom, Prefixes, Pulmonary Artery & Vein, Refraction | 
Carbohydrates are major sources of energy for the body and are found in sugars (fruit, cane sugar, beets) and starches (bread, rice, potatoes, pasta).
Below domain, life is classified into six kingdoms: plants, animals, archaebacteria, eubacteria, and fungi. The last kingdom, protists, include all microscopic organisms that are not bacteria, animals, plants or fungi. (Archaebacteria and eubacteria are sometimes combined into a single kingdom, monera.)
A prefix is added to the base units of the metric system to indicate variations in size. Each prefix specifies a value relative to the base unit in a multiple of 10. Common prefixes are:
| Prefix | Symbol | Relative Value | Example | 
|---|---|---|---|
| mega | M | 106 (1,000,000) | Mm | 
| kilo | k | 103 (1,000) | km | 
| base unit | N/A | 1 | m | 
| centi | c | 10-2 (1/100) | cm | 
| milli | m | 10-3 (1/1,000) | mm | 
The two largest veins in the body, the venae cavae, pass blood to the right ventricle which pumps the blood to the lungs through the pulmonary artery. Blood picks up oxygen in the lungs and returns it to the left atrium via the pulmonary vein.
Because different materials have different refractive indices, light changes speed when passing from one material to another. This causes the light to bend (refraction) at an angle that depends on the change in refractive index between the materials. The greater the difference, the higher the angle of refraction.