CAST Basic Earth and Space Science Review

What is the most abundant gas in Earth's atmosphere?

• Oxygen

• Carbon dioxide

• Nitrogen

• Hydrogen

Answer explanation

Nitrogen is the most abundant gas in Earth's atmosphere, making up about 78% of it. In contrast, oxygen is around 21%, while carbon dioxide and hydrogen are present in much smaller amounts.

What is the name of the process by which rocks are broken down into smaller pieces?

• Erosion

• Weathering

• Deposition

• Sedimentation

Answer explanation

The process by which rocks are broken down into smaller pieces is called weathering. Erosion involves the movement of these particles, while deposition and sedimentation refer to the accumulation of materials.

Which layer of Earth is composed primarily of liquid iron and nickel?

• Inner core

• Outer core

• Mantle

• Crust

Answer explanation

The outer core is the layer of Earth that is primarily composed of liquid iron and nickel, while the inner core is solid, and the mantle and crust are made of different materials.

What type of plate boundary occurs when two tectonic plates move away from each other?

• Convergent boundary

• Divergent boundary

• Transform boundary

• Subduction zone

Answer explanation

A divergent boundary occurs when two tectonic plates move away from each other, leading to the formation of new crust as magma rises to the surface. This is distinct from convergent and transform boundaries.

What term describes the time it takes for half of a radioactive substance to decay?

• Decay constant

• Radioactive cycle

• Half-life

• Geologic age

Answer explanation

The term that describes the time it takes for half of a radioactive substance to decay is called the 'half-life'. This is a key concept in understanding radioactive decay processes.

Tags

NGSS.HS-PS1-8

Which planet in our solar system has the largest volcano, Olympus Mons?

• Earth

• Venus

• Mars

• Jupiter

Answer explanation

Olympus Mons, the largest volcano in our solar system, is located on Mars. It stands about 13.6 miles (22 kilometers) high, making it nearly three times the height of Mount Everest.

What is the primary driver of Earth's weather and climate?

• Ocean currents

• Earth's rotation

• The Sun

• The Moon

Answer explanation

The primary driver of Earth's weather and climate is the Sun. It provides the energy that heats the atmosphere and oceans, influencing weather patterns and climate systems globally.

Tags

NGSS.MS-ESS2-4

NGSS.MS-ESS2-6

What type of rock forms from cooled magma or lava?

• Sedimentary

• Igneous

• Metamorphic

• Fossiliferous

Answer explanation

Igneous rocks form from the cooling and solidification of magma or lava. Sedimentary rocks are formed from the accumulation of sediments, while metamorphic rocks arise from the alteration of existing rocks under heat and pressure.

Earth's magnetic field is generated by the movement of molten metal in the outer core.

• True

• False

Answer explanation

True. Earth's magnetic field is indeed generated by the movement of molten metal in the outer core, a process known as the geodynamo.

The Moon's surface shows no signs of erosion because it lacks water and an atmosphere.

• True

• False

Answer explanation

The statement is true. The Moon's surface is not eroded because it has no water or atmosphere, which are essential for erosion processes like wind and water flow.