ASVAB General Science Practice Test 267463

Questions 5
Topics Acidity, Breathing, Cell Division, Frequency, Troposphere

Study Guide

Acidity

An acid is a substance that gives up positively charged hydrogen ions (H+) when dissolved in water. A base (alkaline) gives up negatively charged hydroxide ions (OH-) when dissolved in water. pH is a scale that measures of how basic or acidic a solution is. Numbered from 0 to 14, solutions with a pH of 7 are neutral, less than 7 are acidic, more than 7 are alkaline.

Breathing

The diaphragm is a system of muscles that allows breathing. During inhalation, the diaphragm expands and air rushes in to fill the space created. Then, during exhalation, the diaphragm contracts and forces the air back out.

Cell Division

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
Frequency

The rate of vibration of sound is called frequency and is measured in hertz (Hz). One hertz is one repetition per second and sounds with high frequency have a higher pitch than sounds with lower frequency. Humans can hear sounds in the range of 20 Hz to 20 kHz.

Troposphere

The Earth's atmosphere has several layers starting with the troposphere which is closest in proximity to the surface. Containing most of the Earth's breathable air (oxygen and nitrogen), it's a region with warmer temperatures closer to the surface and cooler temperatures farther away which results in the rising and falling air that generates weather.