| Questions | 5 |
| Topics | Domain, Fiber, Prefixes, Spinal Cord, Terrestrial Planets |
The broadest classification of life splits all organisms into three groups called domains. The three domains of life are bacteria, archaea and eukaryota.
Fiber provides bulk to help the large intestine carry away waste. Good sources of fiber are leafy vegetables, beans, potatoes, fruits, and whole grains.
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 spinal cord connects the brain to the body's network of nerves. It carries impulses between all organs and the brain and controls simple reflexes.
The four planets closest to the Sun (Mercury, Venus, Earth, and Mars) are called terrestrial (Earth-like) planets because, like the Earth, they're solid with inner metal cores covered by rocky surfaces.