| Questions | 5 |
| Topics | Cell Division, Crust, Element, Outer Planets, Secondary Consumers |
Cell division is the process by which cells replicate genetic material in the nucleus. Cell division consists of several phases:
| Phase | Major Process |
|---|---|
| interphase | chromosomes replicate into chromatids and the cell grows |
| prophase | chromatids pair up |
| metaphase | paired chromatids move to opposite sides of the cell |
| anaphase | cell elongates and nucleus begins to separate |
| telophase | separation of nucleus is complete resulting in two new nuclei |
| cytokinesis | cytoplasm and cell membranes complete their separation resulting in two separate cells |
The crust is the Earth's outermost layer and is divided into oceanic and continental types. Oceanic crust is 3 miles (5 km) to 6 miles (10 km) thick and is composed primarily of denser rock. Continental crust is 20 to 30 miles (30 to 50 km) thick and composed primarily of less dense rock. The crust makes up approximately one percent of the Earth's total volume.
An element is matter than cannot be separated into different types of matter by ordinary chemical methods.
In contrast to the solid terrestrial planets, the outer planets (Jupiter, Saturn, Uranus, and Neptune) consist of hydrogen and helium gas and water.
Secondary consumers (carnivores) subsist mainly on primary consumers. Omnivores are secondary consumers that also eat producers. Examples are rats, fish, and chickens.