ASVAB General Science Practice Test 857904

Questions 5
Topics Medulla, Neutron, Prefixes, Stratus Clouds, Veins

Study Guide

Medulla

Part of the brainstem, the medulla is the connection between the brain and the spinal cord. It controls involuntary actions like breathing, swallowing, and heartbeat.

Neutron

A neutron is a subatomic particle found in the nucleus of an atom. It is neutral as it carries no electric charge.

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
Stratus Clouds

Clouds are categorized based on their shape, size, and altitude. Stratus clouds are low-altitude clouds characterized by horizontal layering with a broad flat base. When stratus clouds occur on the ground the result is fog.

Veins

Veins carry blood back to the heart from the body. While arteries are thick-walled because they carry oxygenated blood at high pressure, veins are comparatively thin-walled as they carry low-pressure deoxygenated blood. Like the heart, veins contain valves to prevent blood backflow.