Test: Our Planet - The Earth - Class 3 MCQ

If the Earth were closer to the Sun, temperatures would rise significantly, making it too hot for most forms of life to survive. The distance from the Sun is crucial in maintaining the right conditions for life, including suitable temperatures and climates.

The atmosphere is the layer of air that surrounds the Earth, composed of various gases including nitrogen, oxygen, and carbon dioxide. This mixture is crucial for supporting life, as it provides the oxygen that animals and humans breathe and the carbon dioxide that plants require for photosynthesis.

The Earth is referred to as the "blue planet" because approximately three-fourths of its surface is covered by oceans, which appear blue from space. This vast coverage of water is essential for life, supporting various ecosystems and providing resources for all living organisms.

The absence of an atmosphere would make life impossible on Earth. The atmosphere provides essential gases for breathing, protects against harmful radiation, and helps regulate temperature, all of which are crucial for sustaining life.

Sunlight is essential for plants as it provides the energy needed for photosynthesis, enabling them to produce food in the form of glucose. This process is fundamental not only for plants but also for the entire food chain, as it supports herbivores and carnivores alike.

Earth is at a perfect distance from the Sun, allowing it to receive enough sunlight to support life while maintaining a temperature range suitable for various ecosystems. This unique positioning is a key factor in the planet's ability to sustain life.

The Earth is spherical in shape, meaning it is round like a ball. This spherical shape allows for the distribution of sunlight and gravity across the planet, facilitating various climates and ecosystems.

Water covers about three-fourths of the Earth's surface, including oceans, rivers, and lakes. This significant presence of water is vital for supporting life and regulating the planet's climate.

Sunlight is crucial for life on Earth as it provides the energy necessary for photosynthesis in plants and helps regulate temperature. This energy supports the growth of plants, which in turn sustain herbivores and the entire food chain.

The term "spherical" refers to a shape that is round, like a ball or an orange. This description is used to explain the Earth's shape and how it affects various physical processes, such as gravity and climate.

Oxygen is the gas that humans and animals need to breathe in order to survive. It is a crucial component of the atmosphere and is produced by plants during photosynthesis, highlighting the interconnectedness of life on Earth.

The Earth is approximately spherical but has a slight bulge at the equator due to its rotation. This shape allows for gravity to pull everything towards the center, creating a balanced environment for life.

The hydrosphere refers to all the water present on Earth's surface, including oceans, rivers, lakes, and glaciers. This vast amount of water is essential for sustaining life and regulating climate.

Plants utilize carbon dioxide during photosynthesis, a process that converts sunlight, water, and carbon dioxide into glucose and oxygen. This process is vital for plant growth and also produces the oxygen that many living organisms need to survive.

The atmosphere serves multiple functions, including providing air to breathe, protecting Earth from harmful solar radiation, and regulating temperature. Its composition is vital for sustaining life and fostering a habitable environment.

Water is vital for life because it covers about three-fourths of Earth's surface, making it essential for all living organisms. It is necessary for hydration, nutrient transport, and many biological processes. Without water, life as we know it could not exist.

Humans cannot survive without drinking water for more than a few days. Water is crucial for nearly all bodily functions, including digestion, temperature regulation, and waste elimination.

Great sailors proved the Earth is round by sailing around it, starting from one point and returning to the same point. Their explorations provided practical evidence of the Earth's spherical shape, which was later confirmed by photographs taken from space.

If the Earth were farther from the Sun, it would experience much colder temperatures, potentially making it impossible for life as we know it to exist. The current distance allows for moderate temperatures that are suitable for living organisms.

The Earth is unique in our solar system because it is the only planet known to support life. This is due to its suitable distance from the Sun, presence of water, and the right atmospheric conditions.