The question asks to identify the gas that constitutes the highest percentage (approximately 78%) of the Earth's atmosphere. This requires knowledge of the composition of atmospheric air.
D) Nitrogen — Nitrogen makes up about 78% of the Earth's atmosphere by volume, making it the most abundant gas.
The question asks for the approximate percentage of oxygen in the Earth's atmosphere. This is a fundamental fact about atmospheric composition that is commonly taught in general science and environmental studies.
The Earth's atmosphere is composed of approximately 78% nitrogen, 21% oxygen, 0.9% argon, and 0.04% carbon dioxide, along with trace amounts of other gases and water vapor.
Therefore, oxygen makes up about 21% of the atmospheric air.
D) About 21% is the correct answer because oxygen constitutes approximately 21% of the Earth's atmosphere by volume.
The question asks about the composition of air, specifically identifying gases present in small amounts besides nitrogen and oxygen. Recall the general composition of Earth's atmosphere to determine the correct option.
Correct Option: B) Carbon dioxide, water vapour and other gases like argon
The question asks about the tiny solid particles present in atmospheric air, in addition to various gases. We need to identify which of the given options correctly lists these solid particles.
A) Dust, smoke and pollen grains are all examples of tiny solid particles that are commonly found suspended in atmospheric air. Dust originates from various sources like soil erosion, construction, and industrial activities. Smoke is produced by incomplete combustion of organic matter. Pollen grains are released by plants for reproduction and become airborne.
The question asks about the primary gas required by living organisms for respiration. Respiration is a fundamental biological process that releases energy from food, and it involves the exchange of gases with the environment.
Correct Option: C) Oxygen is the gas primarily required by living organisms for the process of respiration (breathing).
The question asks to identify the gas that plants utilize during photosynthesis, along with water and sunlight, to produce their food. This requires knowledge of the basic inputs for the photosynthesis process.
D) Carbon dioxide is the gas that plants use, along with water and sunlight, to prepare their food during photosynthesis. It is a crucial reactant in the process, providing the carbon atoms needed to build glucose molecules.