Aerosols reduce primary productivity by :

Options

A. Decreasing `O_(2)` concentration
B. Competing with `CO_(2)`
C. Preventing `N_(2)` fixation
D. Reduction photosyntheis .

Answer

To solve the question "Aerosols reduce primary productivity by:", we can follow these steps:

### Step 1: Understand Aerosols
Aerosols are tiny solid or liquid particles suspended in the atmosphere. They can come from various sources, including natural events (like volcanic eruptions) and human activities (like burning fossil fuels).

**Hint:** Remember that aerosols can be either solid or liquid particles in the air.

### Step 2: Identify the Impact of Aerosols
Aerosols can affect the environment in several ways, including altering the amount of sunlight that reaches the Earth's surface. This is known as the albedo effect, where certain particles reflect sunlight back into space.

**Hint:** Consider how aerosols might influence sunlight and temperature.

### Step 3: Relate to Primary Productivity
Primary productivity refers to the rate at which plants and other photosynthetic organisms produce organic compounds (like glucose) from carbon dioxide and sunlight. If sunlight is reduced due to aerosols, it can hinder the process of photosynthesis.

**Hint:** Think about how plants use sunlight for photosynthesis.

### Step 4: Evaluate the Options
The options given are:
- A) Decreasing oxygen concentration
- B) Competing with carbon dioxide
- C) Preventing nitrogen fixation
- D) Reducing photosynthesis

Among these options, reducing photosynthesis (Option D) directly relates to how aerosols affect the amount of sunlight available for plants.

**Hint:** Focus on the process that directly involves sunlight and plant growth.

### Step 5: Conclusion
Based on the understanding that aerosols increase atmospheric albedo, leading to a decrease in sunlight reaching the plants, the correct answer is that aerosols reduce primary productivity by reducing photosynthesis.

**Final Answer:** D) Reducing photosynthesis

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