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, we will analyze each statement one by one.

### Step 1: Analyze Statement 1
**Statement 1:** "GFC is the major conduit of energy flow in an aquatic ecosystem."
- GFC stands for Grazing Food Chain. In an aquatic ecosystem, the Grazing Food Chain does play a significant role in energy flow, but it is not the only conduit. The Detritus Food Chain (DFC) also plays an important role, especially in nutrient cycling. Therefore, this statement is **incorrect**.

### Step 2: Analyze Statement 2
**Statement 2:** "Source of energy in the detritus food chain is not directly the sun."
- The Detritus Food Chain starts with dead and decaying organic matter, which does not derive its energy directly from sunlight. Instead, it relies on decomposers breaking down this organic matter. Hence, this statement is **correct**.

### Step 3: Analyze Statement 3
**Statement 3:** "Detritus food chain may be connected to grazing food chain somewhere."
- The Detritus Food Chain and Grazing Food Chain can indeed be interconnected. For example, decomposers in the DFC can break down organic matter that can then be utilized by primary producers in the GFC. Therefore, 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."
- In a Grazing Food Chain, as we move up trophic levels (from primary consumers to secondary and tertiary consumers), the size of organisms typically increases. Larger predators are found at higher trophic levels, while smaller herbivores are at lower levels. Therefore, this statement is **incorrect**.

### Conclusion
Now we summarize the correctness of each statement:
1. Incorrect
2. Correct
3. Correct
4. Incorrect

Thus, **2 statements are correct** (Statements 2 and 3).

### Final Answer
The number of correct statements about food chains is **2**.

---