Exploring Soils and the Solar System

What is the main component of clay soil?

• Sand

• Silt

• Clay

• Gravel

Answer explanation

The main component of clay soil is clay itself. Clay particles are very small and compact, which gives clay soil its characteristic properties, such as high water retention and low drainage.

Why is humus important for soil?

• It makes the soil dry

• It provides nutrients to plants

• It makes the soil sandy

• It removes water from the soil

Answer explanation

Humus is crucial for soil because it provides essential nutrients to plants, enhancing their growth and health. It improves soil fertility, unlike the other options which either dry out or alter the soil negatively.

Which layer of soil is known as topsoil?

• Bedrock

• Subsoil

• Humus

• Topsoil

Answer explanation

Topsoil is the uppermost layer of soil, rich in organic material and nutrients, making it crucial for plant growth. It is distinct from subsoil and bedrock, which lie beneath it.

What is one effect of an earthquake?

• Formation of new planets

• Shaking of the ground

• Eruption of volcanoes

• Creation of new soil

Answer explanation

One primary effect of an earthquake is the shaking of the ground, which occurs due to the sudden release of energy in the Earth's crust. This shaking can cause significant damage to structures and landscapes.

How do volcanoes create new landforms?

• By melting ice

• By erupting lava that cools and hardens

• By causing earthquakes

• By growing plants

Answer explanation

Volcanoes create new landforms by erupting lava that cools and hardens. This process forms solid rock structures, such as islands and mountains, contributing to the Earth's landscape.

Which planet is known as the "Red Planet"?

• Earth

• Mars

• Jupiter

• Venus

Answer explanation

Mars is known as the "Red Planet" due to its reddish appearance, which is caused by iron oxide (rust) on its surface. This distinguishes it from Earth, Jupiter, and Venus, making Mars the correct answer.

What type of soil is best for growing plants?

• Sandy soil

• Clay soil

• Loamy soil

• Rocky soil

Answer explanation

Loamy soil is the best for growing plants because it has a balanced mixture of sand, silt, and clay, providing good drainage, nutrient retention, and aeration, which are essential for healthy plant growth.

What does humus add to the soil?

• Rocks

• Nutrients

• Sand

• Water

Answer explanation

Humus enriches the soil by adding essential nutrients that support plant growth. Unlike rocks, sand, or water, nutrients from humus improve soil fertility and structure.

Which layer of soil contains the most organic material?

• Bedrock

• Subsoil

• Topsoil

• Parent material

Answer explanation

Topsoil is the uppermost layer of soil and contains the highest concentration of organic material, such as decomposed plants and animals, making it crucial for plant growth.

What is a common result of a volcanic eruption?

• Formation of glaciers

• Creation of new islands

• Increase in rainfall

• Growth of forests

Answer explanation

A common result of a volcanic eruption is the creation of new islands, as lava can build up and emerge from the ocean floor, forming land. This process is evident in places like the Hawaiian Islands.