The chemical and physical composition of soil is an example of

1. Analyze the question The question asks which type of ecological (environmental) factor covers the chemical and physical makeup of soil.

2. Explain the concept Ecological factors that affect living things are grouped into:

• Climatic factors: light, temperature, rainfall, humidity, wind
• Topographic factors: physical features of the land, such as altitude, slope, and the direction a slope faces
• Edaphic factors: everything to do with the soil, including its pH, mineral salts, texture, structure, water-holding capacity, humus content, and air spaces
• Biotic factors: living organisms such as plants, animals, and microbes

The word "edaphic" comes from the Greek edaphos, meaning "soil" or "ground".

3. Step-by-step solution

• Soil composition, both chemical (minerals, pH, nutrients) and physical (texture, structure, porosity), is about the soil itself.
• Option A (climatic) is about weather, so it is wrong.
• Option B (topographic) is about the shape and height of the land, so it is wrong.
• Option D (chemical factor) is not a standard category of ecological factors. It also covers only the chemical part, while the question includes the physical part too.
• Option C (edaphic) is the factor that covers all soil properties, so it fits.

4. Answer The correct option is C. Edaphic factor.

5. Exam tip Link Edaphic with Earth: edaphic means soil. When you see "soil" in an ecology question, think edaphic. Also remember Topographic means land features, like a topographic map.