Test: Soil, Rocks & Minerals - 1 - Class 5 MCQ

All of the factors like ploughing of hill slops, overgrazing , floods and deforestation are responsible for soil erosion. 

Sunlight and rain cause heating and cooling of rocks which by weathering gives rise to soil.

Explanation:
The correct answer is C: Bunds.
Definition:
- Bunds are tall mud walls built on the sides of rivers or streams to conserve soil and prevent erosion.
Features of Bunds:
- Bunds are typically built in agricultural areas where there is a risk of soil erosion due to water flow.
- They are constructed perpendicular to the water flow, creating a barrier that slows down the speed of the water and reduces its erosive force.
- Bunds are usually made of locally available materials such as mud, stones, or concrete.
- They are built in a stepped or terraced pattern to provide additional stability and prevent collapse.
- Bunds can be reinforced with vegetation, such as grass or shrubs, to further strengthen the structure and enhance soil conservation.
Benefits of Bunds:
- Bunds help to prevent soil erosion by reducing the impact of water flow and preventing sediment from being washed away.
- They conserve soil fertility by reducing nutrient loss through erosion.
- Bunds also help to retain moisture in the soil, improving water availability for plants and crops.
- They can also act as flood control measures by diverting or slowing down water flow during heavy rainfall.
Conclusion:
Tall mud walls built on the sides of rivers to conserve soil are called bunds. These structures play a crucial role in preventing soil erosion, conserving soil fertility, and improving water management in agricultural areas.

Not a type of rock:
- Lava: Lava is not a type of rock. It is molten rock that is expelled by a volcano during an eruption. Lava eventually cools and solidifies to form igneous rocks, but it is not a rock itself.
Types of rocks:
- Igneous: Igneous rocks are formed from the cooling and solidification of molten rock material (magma or lava). Examples include granite and basalt.
- Sedimentary: Sedimentary rocks are formed from the accumulation and consolidation of sediments. These sediments can be derived from the weathering and erosion of other rocks, as well as the remains of plants and animals. Examples include sandstone and limestone.
- Metamorphic: Metamorphic rocks are formed from the transformation of existing rocks under high heat and pressure. This process causes the minerals and texture of the rocks to change. Examples include marble and slate.
Conclusion:
- Lava is not a type of rock, but rather the molten form of rock material. It eventually solidifies to form igneous rocks. Therefore, the correct answer is C: Lava.

When is Earth Day celebrated?
Earth Day is celebrated on April 22nd every year.
Explanation:
Earth Day is an annual event celebrated globally to demonstrate support for environmental protection. It aims to raise awareness about environmental issues and promote sustainable practices. Here is a detailed explanation of why Earth Day is celebrated on April 22nd:
1. Origins of Earth Day:
- Earth Day was first celebrated on April 22, 1970, in the United States.
- It was founded by Senator Gaylord Nelson, an environmental activist, who wanted to bring national attention to the environmental crisis.
2. Significance of April 22nd:
- April 22nd was chosen as Earth Day because it falls between spring break and final exams, making it convenient for college students to participate.
- This date also aligns with the birth of the modern environmental movement, as it was inspired by the anti-war protests of the late 1960s.
3. Global Recognition:
- Earth Day gained international recognition in 1990 when it was celebrated in multiple countries around the world.
- Today, Earth Day is observed in more than 193 countries, making it the largest civic observance in the world.
4. Activities and Awareness:
- On Earth Day, people participate in various activities such as tree planting, beach cleanups, recycling drives, and environmental education programs.
- It serves as a reminder for individuals, communities, and governments to take action towards protecting the planet and preserving its resources.
In conclusion, Earth Day is celebrated on April 22nd to raise awareness about environmental issues and promote sustainable practices. It serves as a global platform for individuals and organizations to come together and take action towards a greener and more sustainable future.

Soil erosion can be prevented by implementing various measures. Some of the effective methods to prevent soil erosion are:

• Terrace farming: This technique involves creating flat platforms on slopes to control water runoff. It helps to slow down the flow of water and allows it to seep into the soil, reducing erosion.


• Afforestation: Planting trees and vegetation helps to stabilize the soil. The roots of plants hold the soil together, preventing erosion caused by wind and water.


• Building bunds: Bunds are barriers constructed across the slope to reduce water velocity and prevent soil erosion. They can be made using stones, logs, or even grass, and help in retaining water and preventing runoff.

By implementing these measures, soil erosion can be effectively prevented. Therefore, the correct answer is D: All the above.

Metamorphic rocks can be formed by pressure deep under the Earth's surface, from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates. Examples of metamorphic rocks include anthracite, quartzite, marble, slate, granulite, gneiss and schist.

Answer:
About 95% of Earth's crust is made up of igneous rocks.
Explanation:
Igneous rocks are formed from the solidification of molten material, either magma or lava, which cools and crystallizes. They are the most abundant type of rock found in the Earth's crust, accounting for about 95% of its composition. Here are some key points to understand:
- Igneous rocks:
- Formed from the solidification of molten material (magma or lava).
- Classified into two categories: intrusive (formed underground) and extrusive (formed on the surface).
- Examples include granite, basalt, and obsidian.
- They have a crystalline structure due to the cooling and solidification process.
- Sedimentary rocks:
- Formed from the accumulation and compaction of sediments over time.
- Examples include sandstone, limestone, and shale.
- They often contain fossils and are layered in nature.
- Metamorphic rocks:
- Formed from the transformation of existing rocks under high heat and pressure.
- Examples include marble, slate, and gneiss.
- They have a distinct texture and often show signs of recrystallization.
- All the above (Option D):
- This option is incorrect as only igneous rocks make up about 95% of the Earth's crust, not all three types of rocks.
Therefore, the correct answer is B: Igneous rocks, as they comprise the majority of the Earth's crust composition.

Explanation:
To determine which option is the correct answer, we need to consider the characteristics given in the question.
Given:
- The material is porous.
- The material is formed from lava.
Options:
A. Sandstone
B. Pumice
C. Granite
D. Obsidian
E. None of these

1. Characteristics:
- Porous: Having small holes or spaces that allow liquid or air to pass through.
- Formed from lava: Created through the cooling and solidification of molten rock material.
2. Evaluating the Options:
A. Sandstone:
- Sandstone is a sedimentary rock formed from sand grains.
- It is not formed from lava, so it does not meet the given criteria.
B. Pumice:
- Pumice is a volcanic rock with a highly porous structure.
- It is formed from lava during volcanic eruptions.
- Pumice meets both the criteria given in the question.
C. Granite:
- Granite is an igneous rock composed of minerals such as quartz, feldspar, and mica.
- It is not formed from lava, but instead from the slow cooling of magma beneath the Earth's surface.
D. Obsidian:
- Obsidian is a natural glass formed from rapidly cooling lava.
- While it is formed from lava, it is not porous.
E. None of these:
- This option can be eliminated as we have identified a suitable answer.
3. Conclusion:
- Based on the given characteristics, the correct answer is Pumice (Option B).
- Pumice is porous and formed from lava, making it the best fit for the given criteria.