Which one of the following exhibits least productivity?

Options

A. Salty marshes
B. Grasslands
C. Open oceans
D. Coral reefs

Answer

To determine which ecosystem exhibits the least productivity, we need to analyze the productivity of each option provided. Here’s a step-by-step breakdown of the solution:

### Step 1: Understand the Concept of Productivity
- **Definition**: Productivity in an ecosystem refers to the rate at which biomass is generated. It indicates how much organic matter is produced by plants (through photosynthesis) and is available for consumption by other organisms in the food chain.

### Step 2: Analyze Each Option
1. **Salty Marshes**:
- These areas have brackish water (a mix of fresh and salty water) and support plants known as helophytes, which can tolerate high salt levels.
- They utilize tidal movements to obtain nutrients and have a relatively high productivity due to the presence of photosynthetic plants.

2. **Grasslands**:
- Grasslands are open areas that receive direct sunlight, but they can experience temperature fluctuations that may limit plant growth.
- While they have some productivity, it is generally lower compared to more nutrient-rich ecosystems.

3. **Open Oceans**:
- Open oceans cover a vast area but have limited sunlight penetration, especially in deeper waters.
- The lack of sunlight restricts photosynthesis, resulting in low productivity levels.

4. **Coral Reefs**:
- Coral reefs are known for their high productivity due to the symbiotic relationship between corals and algae.
- Algae perform photosynthesis and provide nutrients, leading to a high rate of biomass generation.

### Step 3: Compare the Productivity Levels
- Based on the analysis:
- **Salty Marshes**: High productivity
- **Grasslands**: Moderate productivity
- **Open Oceans**: Least productivity due to limited sunlight
- **Coral Reefs**: Maximum productivity

### Step 4: Conclusion
- After evaluating all the options, it is clear that **open oceans exhibit the least productivity** among the ecosystems listed.

### Final Answer
The ecosystem that exhibits the least productivity is **Open Oceans**.

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