All questions of Environment for Class 7 Exam

Photosynthesis in plants requires carbon dioxide, which is absorbed from the atmosphere, along with sunlight and water, to produce food and oxygen.

The hydrosphere includes all water bodies on Earth, such as rivers, lakes, and oceans, which are essential for supporting aquatic life.

They takes millions of years to decompose in the soil . As they cannot be burnt, if it was burnt it releases harmful gas which cause air pollutions . As they don't decompose in the soil so,they are non biodegradable.

Biotic components (living organisms) depend on abiotic components (non-living elements) such as water, air, and soil for their survival and growth in an ecosystem.

Constructing dams is a human activity that modifies the environment by altering natural water flow and creating reservoirs.

Barter trade

The lithosphere is the solid crust or the hard-top layer of the earth, which is primarily composed of rocks and minerals. This layer is essential for providing the foundation for landforms and soil that supports plant life.

The biotic environment includes living components such as plants and animals, which interact and depend on each other for survival.

Interaction of Early Humans with Their Environment
Early humans had a profound connection with their environment, which was crucial for their survival and development. Their interactions can be summarized as follows:
Adaptation to Natural Surroundings
- Early humans lived in diverse environments, from forests and plains to deserts and mountains.
- They adapted their lifestyles based on the specific resources available in their surroundings.
Utilization of Available Resources
- Early humans were primarily hunter-gatherers, relying on hunting animals and gathering plants for food.
- They used tools made from stones, bones, and wood, which they crafted from materials found in their environment.
Building Shelter and Clothing
- They created shelters using local materials like wood, leaves, and animal skins to protect themselves from weather and predators.
- Clothing was made from animal hides, helping them adapt to varying climates.
Understanding Ecosystems
- Early humans developed an understanding of seasonal changes, animal migrations, and plant growth cycles, which guided their foraging and hunting practices.
- This knowledge allowed them to live sustainably and maintain a balance with nature.
Respect for Nature
- Early humans exhibited a sense of respect for nature as they depended on it for survival.
- They practiced selective hunting and foraging, ensuring that they did not over-exploit resources.
In summary, early humans interacted with their environment by adapting to their surroundings, utilizing available resources, and maintaining a harmonious relationship with nature. This approach ensured their survival and laid the foundation for future human development.

The biosphere is a narrow zone of the Earth where land, water, and air interact to support life, encompassing the entire plant and animal kingdom.

The Main Function of the Atmosphere
The atmosphere is crucial for sustaining life on Earth. Its primary role is to serve as a protective layer that surrounds our planet. Here’s a detailed explanation of why option 'C' is correct:
1. Protective Blanket
- The atmosphere acts as a shield, protecting the Earth from harmful solar radiation, particularly ultraviolet (UV) rays.
- It helps to moderate temperatures, ensuring that they remain within a range conducive to life.
2. Essential for Weather and Climate
- The atmosphere plays a vital role in weather patterns, influencing precipitation and temperature.
- It facilitates the water cycle, which is essential for ecosystems, agriculture, and drinking water.
3. Supports Life
- The atmosphere contains essential gases, including oxygen for respiration and carbon dioxide for photosynthesis.
- It allows for the existence of diverse ecosystems by maintaining a stable environment.
4. Facilitates Communication and Transportation
- The atmosphere enables the transmission of sound and radio waves, vital for communication.
- It allows for air travel, connecting people and cultures across the globe.
5. Maintains Pressure
- The atmospheric pressure is crucial for maintaining the integrity of living organisms.
- It influences the boiling point of water, which is significant for life processes.
In conclusion, the atmosphere serves as a vital blanket of air surrounding the Earth, protecting life, regulating climate, and providing essential gases, making option 'C' the correct answer.

Plants and animals are interdependent; plants provide food and habitats for animals, while animals assist in pollination and seed dispersal, facilitating plant reproduction and growth.

Definition of Ecosystem
An ecosystem can be defined as a community of living organisms interacting with each other and their physical environment. It includes all the plants, animals, and microorganisms in a given area, as well as the non-living components like soil, water, and air.

Components of an Ecosystem
- Living organisms: These include producers, consumers, and decomposers that interact with each other for energy and nutrients.
- Physical environment: This comprises abiotic factors like temperature, sunlight, water, and soil that influence the ecosystem.

Interactions in an Ecosystem
- Organisms within an ecosystem rely on each other for food, shelter, and other resources.
- Energy flows through the ecosystem in the form of food chains and food webs.
- Nutrients are cycled within the ecosystem through processes like decomposition and nutrient absorption.

Importance of Ecosystems
Ecosystems provide numerous benefits to humans and the environment, including:
- Regulation of climate
- Provision of food and resources
- Maintenance of biodiversity
- Support for clean air and water

Conclusion
In conclusion, an ecosystem is a complex network of interactions between living organisms and their environment. Understanding ecosystems is crucial for conservation efforts and sustainable management of natural resources.

The natural environment encompasses elements created by nature, including land, water, air, plants, and animals, which form the basis of life on Earth.

The lithosphere is the solid crust or the hard-top layer of the earth, composed of rocks and minerals, and is covered by a thin layer of soil.