Model Papers -1 - Class 4 MCQ

Oxygen levels are lowest at night because plants stop photosynthesis (which produces oxygen) and consume oxygen during respiration.

The needle-like leaves of the cactus help reduce water loss by evaporation, enabling it to survive in the desert’s dry environment.

They rob soil moisture and nutrients from the competing crop and decrease harvest efficiencies. Weeds also compete with the crop for sunlight. Because they are plants competing to survive in a limited space, weeds are actively removing nutrients from the soil to grow taller, stronger and healthier each day.

Birds with gliding wings are built for long-distance flight with minimal energy use, typically used for soaring across large areas.

The classification is based on their physical characteristics: spiders are arachnids, butterflies are insects, snails are mollusks, and earthworms are annelids.

The correct food chain pyramid starts with producers (plants), followed by herbivores (cows), and then carnivores/omnivores (whales).

Hard water, rich in calcium and magnesium, makes it difficult for soap to lather and takes longer to rinse off.

Since, Flask A is connected to flask B, the water is converted into vapors by the process of evaporation, these vapors then reach Flask B where they are again converted to water. so, almost the same amount of water is transferred.  

The diagram likely shows evaporation (liquid turning into vapor) and precipitation (water vapor condensing and falling as liquid).

The troposphere is the lowest layer of Earth's atmosphere, where weather and most living organisms exist.

After the hot metal ball is placed in the cooler water, the temperature of the water will rise toward the temperature of the ball, but it will not exceed 100°C.

The correct statement is D: Grand Trunk Road is a national highway.

Explanation:

• The Grand Trunk Road is one of the oldest and longest major roads in Asia, running from Bangladesh to Pakistan, passing through India.


• It serves as a major national highway, facilitating trade and travel across northern India.


• It has historical significance and is crucial for national connectivity.

 

Vehicles for the disabled are designed with accessibility features to aid people with disabilities, such as ramps and special seating.

Birds communicate through singing and various vocalizations, which serve to attract mates and defend territories.

Proteins are essential nutrients found in animal and plant products and are crucial for building and repairing tissues.

The images likely show the respiratory system, which is responsible for the exchange of gases (oxygen and carbon dioxide) in the body.

The cell membrane is selectively permeable, allowing only certain substances to enter or leave the cell.

Frying eggs is a chemical change because it involves the denaturation of proteins in the egg, resulting in a new substance with different properties. The other options involve physical changes, where the substance's chemical structure remains the same.

Circulatory System

- The circulatory system is responsible for transporting blood and nutrients throughout the body.
- When a student scrapes their knee, the body responds by initiating the inflammatory response.
- White blood cells are transported to the wound site through the circulatory system to help fight off any potential infection.
- The white blood cells work to clean up the wound and promote healing by attacking any foreign invaders present.
- The circulatory system plays a crucial role in the body's ability to respond to injuries and protect against infections.

Vegetable cheela (which often contains leafy greens) and milk are good sources of calcium and iron, indicating that Ranchit might have a deficiency in these minerals. The mother is providing a meal rich in these nutrients to address the deficiency.

Aspartame is a sweetener, not a preservative. Sugar, salt, and sodium benzoate are commonly used preservatives.

Graphite is used in pencils because it is soft and can leave a mark on paper.

A balance is used to measure mass, while a microscope, beaker, and graduated cylinder measure other properties.

The surface of Mercury is heavily cratered and lacks atmosphere, much like the Moon.

The inner core, the outer core, mantle and crust are the four layers of earth The Inner Core. It is the centre and the hottest layer of the Earth. The inner core is solid and made up of iron and nickel with temperature up to 5,500 o C. Due to its immense heat energy, the inner core is more like the engine room of the Earth. The Outer Core. The outer core of the Earth is similar to a very hot ball of metals, whose temperature is around 4000 o F to 9000 0 F.

In a motor, electrical energy is converted into kinetic energy, causing the motor to rotate.

Ignoring friction, the minimum effort needed to lift the bucket would equal its weight, which is 5 kg.

A pulley system uses mechanical energy to lift or move objects.

A molecule is made up of two or more atoms bonded together.

This experiment demonstrates that air occupies space, as the water moves into the bottle when the air is sucked out.