How many of the following statements is /are correct about food chains ?
(1 ) GFC is the major conduit of energy flow in an aquatic ecosystem.
(2) Source of energy in the detritus food chain is not directly the sun
(3) Detritus food chain may be connected to grazing food chain somewhere .
(4) In a grazing food chain, the size of organisms always decreases at higher levels.

Options

A. One
B. Two
C. Three
D. Four

Answer

To determine how many of the statements about food chains are correct, let's analyze each statement step by step.

### Step 1: Analyze Statement 1
**Statement 1:** GFC is the major conduit of energy flow in an aquatic ecosystem.

- **Explanation:** GFC stands for Grazing Food Chain. In aquatic ecosystems, the Grazing Food Chain typically starts with producers (like phytoplankton) that utilize sunlight for energy. This energy is then transferred through various trophic levels (consumers). Therefore, this statement is **correct**.

### Step 2: Analyze Statement 2
**Statement 2:** Source of energy in the detritus food chain is not directly the sun.

- **Explanation:** In a detritus food chain, the energy source comes from decomposing organic matter (dead plants and animals), rather than directly from sunlight. Decomposers break down this organic matter to obtain energy. Thus, this statement is also **correct**.

### Step 3: Analyze Statement 3
**Statement 3:** Detritus food chain may be connected to grazing food chain somewhere.

- **Explanation:** Detritus food chains can indeed be connected to grazing food chains. For instance, omnivores can play a role in both food chains. An organism like a crow can act as a primary consumer in the grazing food chain and as a decomposer in the detritus food chain. Hence, this statement is **correct**.

### Step 4: Analyze Statement 4
**Statement 4:** In a grazing food chain, the size of organisms always decreases at higher levels.

- **Explanation:** In a grazing food chain, as you move up the trophic levels, the size of organisms generally increases. For example, plants (producers) are smaller than the primary consumers (like rats), which are smaller than secondary consumers (like snakes), and so on, with top carnivores (like eagles) being larger than all previous levels. Therefore, this statement is **incorrect**.

### Conclusion
Now, let's summarize the correctness of each statement:
1. Correct
2. Correct
3. Correct
4. Incorrect

Thus, **three statements are correct**.

### Final Answer:
The number of correct statements about food chains is **3**.

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