A possible answer to a question or problem is a(n) _____.

A procedure used to test a hypothesis is called a(n) _____.

The part of an experiment in which all conditions are kept the same and is the standard for comparison is the _____.

Which of the following is the part of an experiment that the scientist changes in order to test the hypothesis?

Which of the following parts of an experiment responds to changes made by the scientist?

Which of the following is an explanation of how or why things occur in the natural world?

Which of the following is a prediction of what will happen under certain conditions?

Which of the following is the most common form of matter in the universe?

______ is the most abundant element in the universe.

Which of the following explains the formation of the universe?

The universe is composed of which of the following?

What is responsible for the expansion of the universe?

What evidence exists which shows that the universe is expanding?

Which of the following is a collection of gas, dust, stars, planets, moons, and nebulas that is bound together by gravity?

What is the universal force of attraction that exists between all objects and holds galaxies together and planets in orbit?

If dark energy proves to be stronger than gravity, what will be the fate of the universe?

If gravity proves to be stronger than dark energy, what will be the fate of the universe?

If dark energy and gravity prove to be equal, what will be the fate of the universe?

A cloud of gas and dust in which stars and planets form is known as a ________.

A large collection of plasma, which is undergoing fusion and is held together by gravity is a _______.

Which of the following is a spinning disk of gases with a hot core, which is the first step in star formation?

_______ is the heaviest element that low mass stars can create during fusion.

_______ is the heaviest element that high mass stars can create during fusion.

Which of the following is the massive explosion of a high mass star when it runs out of elements to fuse?

A _______ is a swollen, expanded, dying low mass star that has run out of hydrogen to fuse.

A _______ is a swollen, expanded, dying high mass star that is fusing elements heavier than hydrogen and helium.

Which of the following is the ejection of gases from a dying low mass star?

Which of the following is the leftover core of a dead low mass star that is no longer fusing elements?

Which of the following is the undetectable remains of a dead low mass star after it has completely cooled?

A _______ is the leftover core after a supernova of a high mass star that was less than 20 times the mass of the sun?

A _______ is the leftover core after a supernova of a high mass star that was more than 20 times the mass of the sun?

Which of the following is true of white dwarf stars?

Two identical stars have the same luminosity. The star that is closer to Earth will appear brighter because it has a higher ______.

What happens to a star each time it fuses a heavier element or tries to fuse a heavier element?

Mature stars that are currently fusing hydrogen and have not run out of fuel are called _________.

A star and all the celestial objects that revolve around it is called a __________.

Planets that orbit stars other than the sun are known as ________.

Which of the following is a layer of the sun’s atmosphere?

Which layer of the sun’s atmosphere is the hottest?

Which layer of the sun’s atmosphere is the surface layer of the sun from which light photons are emitted?

Which of the following are dark areas on the surface of the photosphere that are associated with solar flares?

Which of the following are eruptions of gases from the sun that often disrupt telecommunications?

Which of the following is a constant flow of charged particles from the sun?

Planets located between the sun and the asteroid belt are known as __________.

Planets located beyond the asteroid belt are known as __________.

Planets that are small and rocky are known as __________.

Large gaseous planets are known as __________.

Planets are formed by which process?

Which model of the solar system has Earth in the center with the sun and the other planets revolving around it?

Which model of the solar system has the sun in the center with Earth and the other planets revolving around it?

Who discovered that planets orbit the sun in ellipses and that planets closer to the sun orbit faster?

Why is Venus the hottest planet in the solar system even though it is not the closest planet to the sun?

Why is Mercury not the hottest planet in the solar system even though it is the closest planet to the sun?

Which of the following would be true of a planet with no atmosphere?

Which of the following would be true of a planet with a very dense atmosphere?

Which planets in the solar system have rings around them?

Which planet is tilted 90⁰ on its axis and rotates end over end like a bowling ball?

Which planet is has a retrograde rotation and spins the opposite direction from all the other planets?

Why does Mars appear reddish in color?

Olympus Mons is the tallest peak in the solar system. On what planet is it located?

What is significant about Jupiter’s moon, Ganymede?

What is significant about Jupiter’s moon, Io?

What is significant about Neptune’s moon, Triton?

How far is one Astronomical Unit, which is used to measure distances in the solar system?

What is Earth's average distance from the sun?

Why is Earth an oblate spheroid?

The motion of Earth as it spins on its axis is its ___________.

The motion of Earth as it goes around the sun is its ___________.

The shape of Earth’s orbit around the sun is a(n) ___________.

Which of the following is a measurement of time based on when stars other than the sun appear in the same place in the night sky?

Which of the following is the apparent movement of the sun from noon until noon 24 hours later?

An astronomical event that occurs when the moon lines up between Earth and the sun is a ___________.

An astronomical event that occurs when Earth lines up between the moon and the sun is a ___________.

Which of the following is occurring when the appearance of the moon decreases in size each night?

Which of the following is occurring when the appearance of the moon increases in size each night?

Which of the following is true of Earth’s moon?

Why does everyone on Earth always see the same side of the moon?

What creates Earth’s magnetic field?

Which of the following causes seasons on Earth?

When does the sun’s rays strike north or south of the equator?

When does the sun’s rays strike the equator directly?

Which of the following is true of Earth’s magnetic field?

Which of the following is caused by solar wind being deflected off Earth’s magnetic field?

Which of the following are lunar highlands, which are the light colored areas on the moon?

Which of the following are lunar lowlands, which are the dark colored areas on the moon?

Which of the following are meandering valleys on the surface of the moon?

______ are trails of ejecta that extend outward in all directions from impact craters on the moon.

______ is loose rocks and debris on the surface of the moon.

How did Aristotle know that Earth was round even before telescopes and space travel?

Which of the following is the amount of sunlight that is reflected from moons and planets?

Why is a solar day slightly longer than a sidereal day?

How long does it take Earth to revolve around the sun one time?

How long does it take Earth to rotate on its axis one time?

Which of the following geologic time units is the largest?

During which era were microorganisms the only form of life on Earth?

During which era were ocean dwelling organisms the predominant form of life on Earth?

During which era were dinosaurs the predominant form of life on Earth?

During which era were mammals the predominant form of life on Earth?

During which event did an abundance of multicellular life first appear on Earth?