ASVAB General Science Practice Test 548842

Questions 5
Topics Crust, Doppler Effect, Genetic Type, Health Benefits of Vitamins & Minerals, Prefixes

Study Guide

Crust

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.

Doppler Effect

The Doppler effect occurs when the source or listener (or both) of sound waves is moving. If they're moving closer together, the listener perceives the sound with a higher pitch and, when they're moving apart, the listener perceives the sound with a lower pitch.

Genetic Type

A person's genotype is their genetic makeup and includes both dominant and recessive alleles. Phenotype is how the genes express themselves in physical characteristics.

Health Benefits of Vitamins & Minerals
Vitamin / Mineral Sources Health Benefits
Calcium Dairy products (milk, yogurt, cheese), spinach. Aids bone growth and repair, muscle function.
Iron Red meat, beans, whole grains. Allows red blood cells to transfer oxygen to body tissues.
Magnesium Nuts, whole grains, green leafy vegetables. Muscle, nerve, and enzyme function.
Potassium Bananas, nuts, seeds. Helps balance fluid levels in the body.
Vitamin A Liver, milk, eggs, carrots. Vision, immune system, cell growth.
Vitamin C Green and red peppers, citrus fruits, broccoli. Collagen formation, immune system function, antioxidant (helps protect cells from damage).
Vitamin D Exposure to sunlight. Helps calcium strengthen bones, muscle, nerve, and immune system function.
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