The Earth's crust is primarily composed of oxygen, which combines with silicon to form silicate minerals.

The Earth's crust is primarily composed of basalt (oceanic crust) and granite (continental crust).

The inner core is primarily composed of solid iron, along with some nickel.

The outer core is primarily composed of liquid iron and nickel, which is crucial for generating the Earth's magnetic field.

Latitude is the primary factor that affects climate in a region, as it determines the angle of sunlight received.

All of the above factors affect soil erosion rate.

Temperature is the primary factor that affects the state of matter by influencing particle energy.

The Beti Bachao Beti Padhao scheme focuses on improving the sex ratio and promoting education for girls.

The primary function of carbohydrates in the body is to provide energy, especially for the brain and muscles.

The primary function of dietary fats is energy storage, providing 9 calories per gram.

Fats primarily serve as energy storage, providing 9 calories per gram.

Root hairs increase the surface area of roots, enhancing the plant's ability to absorb water and nutrients from the soil.

The cell membrane regulates what enters and exits the cell, maintaining homeostasis.

The circulatory system is responsible for transporting nutrients, oxygen, and waste products throughout the body.

The primary function of the digestive system is to break down food and absorb nutrients, making option 1 the correct answer.

The primary function of the Election Commission of India is to conduct free and fair elections in the country.

The integumentary system, which includes the skin, hair, and nails, serves to protect the body, regulate temperature, and provide sensory information.

Mitochondria are known as the powerhouse of the cell, where cellular respiration occurs to produce ATP.

The primary function of the respiratory system is to exchange gases, specifically to take in oxygen and expel carbon dioxide.

Ribosomes are the cellular structures responsible for synthesizing proteins by translating messenger RNA (mRNA).

Carbon Dioxide is the primary gas responsible for the greenhouse effect.

Seismic waves generated by earthquakes are the primary method used to study the Earth's interior structure.

The Pradhan Mantri Awas Yojana aims to provide affordable housing to the urban poor and ensure housing for all by the year 2022.

The complete combustion of propane produces carbon dioxide (CO2) and water (H2O) as primary products.

The reaction produces a salt, water, and carbon dioxide.

The reaction produces sodium chloride, carbon dioxide, and water.

The Earth's magnetic field is primarily generated by the flow of molten iron in the outer core.

Tectonic plates move primarily due to convection currents in the mantle, which are caused by the heat from the Earth's core.

The primary reason for the occurrence of seasons on Earth is the tilt of the Earth's axis.

Gases fill their containers due to high kinetic energy, which allows particles to move freely and spread out.