ASVAB General Science Practice Test 585561

Questions 5
Topics Atomic Mass, Capillaries, Central & Peripheral Nervous Systems, Prefixes, Traits

Study Guide

Atomic Mass

The atomic mass of an element listed in the Periodic Table represents the average mass of a single atom of that element and is measured in atomic mass units (amu). This number is an average as some elements have isotopes with atoms that vary in their number of neturons and, therefore, differ in weight.

Capillaries

Capillaries are small thin-walled vessels that permit the exchange of oxygen, carbon dioxide, nutrients, and waste between blood and the body's cells. This process of exchange is called diffusion.

Central & Peripheral Nervous Systems

The nervous system consists of the brain and spinal cord (central nervous system) and the peripheral nervous system which is the network of nerve cells (neurons) that collect and distribute signals from the central nervous system throughout the body.

Prefixes

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
Traits

The traits represented by genes are inherited independently of each other (one from the male and one from the female gamete) and a trait can be dominant or recessive. A dominant trait will be expressed when paired with a recessive trait while two copies of a recessive trait (one from each parent) must be present for the recessive trait to be expressed.