About 85 by mass of Earth's core is composed of the element(s)
a. iron
b. nickel
c. oxygen.
d. silicon.
e. iron and nickel.
[Ques. 2] A high-pressure air mass that moves over a region and then becomes stationary may give rise to a(n) ______________ inversion.
Fill in the blank(s) with correct word
[Ques. 3] About 99 by mass of Earth's atmosphere is composed of the two elements
a. nitrogen and oxygen.
b. oxygen and carbon dioxide.
c. oxygen and silicon.
d. hydrogen and helium.
[Ques. 4] Coal, gas, and oil are ______________ fuels.
Fill in the blank(s) with correct word
[Ques. 5] About 74 by mass of Earth's crust is composed of the two elements
a. oxygen and iron.
b. aluminum and iron.
c. oxygen and silicon.
d. silicon and aluminum.
[Ques. 6] Flashes from unseen lightning are called ______________.
Fill in the blank(s) with correct word
[Ques. 7] When the atoms of two or more elements react chemically, they usually join together to form
a. isotopes.
b. new elements.
c. molecules.
d. isomers.
[Ques. 8] Snowstorms accompanied by high winds and low temperatures are called ______________.
Fill in the blank(s) with correct word
[Ques. 9] What scientist discovered more elements than any other person?
a. Lavoisier
b. Boyle
c. Berzelius
d. Davy
[Ques. 10] When at home during a tornado warning, you should seek shelter in the ______________ of the building.
Fill in the blank(s) with correct word
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