Aircraft often use the "gyro" type of this instrument, as it's unaffected by local magnetic fields
Nearly all of the Earth's weather occurs in this layer of the atmosphere below the stratosphere
About 70% of this pungent gas produced is converted into fertilizer
Anthracite, the highest grade of coal, is composed almost entirely of this element
Scientists once tried to estimate the Earth's age by measuring the level of this substance in the ocean
To properly accessorize your poodle skirt, you had to wear bobby socks & these shoes
In the late 1800s, gowns named for this hot beverage were worn at afternoon gatherings
In some instances, the treatment of leukemia may call for a transplant of this bone tissue
It might ring a "Ma" bell that this 1959 fad requiring groups of people began in South Africa
The cheese steak sandwich is said to have originated in this eastern city in the 1930s