Which one of the following factors is biotic

Options

A. Photoperiod
B. `CO_2` content to the soil
C. Texture and porosity of the soil
D. Mushroom

Explanation

To determine which factor is biotic from the given options, we can follow these steps:

### Step 1: Understand the Definitions
- **Biotic Factors**: These are the living components of an ecosystem, including plants, animals, fungi, and microorganisms.
- **Abiotic Factors**: These are the non-living components of an ecosystem, such as soil, water, air, and sunlight.

### Step 2: Analyze the Options
The options provided are:
1. Photoperiod
2. Carbon dioxide contained in the soil
3. Texture and porosity of the soil
4. Mushroom

### Step 3: Identify Each Option
- **Photoperiod**: This refers to the duration of light in a day. It is an abiotic factor as it relates to the environment.
- **Carbon dioxide contained in the soil**: This is a gas that is part of the atmosphere and is also considered an abiotic factor.
- **Texture and porosity of the soil**: These are physical properties of soil and are classified as abiotic factors.
- **Mushroom**: This is a type of fungus and is a living organism, thus classified as a biotic factor.

### Step 4: Conclusion
From the analysis, the only biotic factor among the options is **Mushroom**.

### Final Answer
The biotic factor from the options given is **Mushroom**.

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