If the concentration of insecticide DDT in a pond water is 0.04 ppm, which of the following sequences of DDT concentration would be correct for algae-fishes-man food chain?

Options

A. Algae `gt` Fishes `lt` Man
B. Algae `gt` Fishes `gt` Man
C. Algae `lt` Fishes `lt` Man
D. Algae `lt` Fishes `gt` Man

Answer

To solve the question regarding the concentration of DDT in a food chain consisting of algae, fishes, and humans, we can follow these steps:

### Step 1: Understand the Concept of Biomagnification
Biomagnification refers to the process where the concentration of a substance, such as an insecticide like DDT, increases as it moves up the food chain. Organisms at higher trophic levels accumulate more of the substance than those at lower levels.

**Hint:** Remember that biomagnification leads to higher concentrations in top consumers.

### Step 2: Identify the Organisms in the Food Chain
In this food chain, we have three levels:
1. Algae (primary producer)
2. Fishes (primary consumer)
3. Humans (top consumer)

**Hint:** Identify the roles of each organism in the food chain to understand how DDT concentration changes.

### Step 3: Determine the DDT Concentration in Each Organism
- **Algae:** Since they are at the base of the food chain, they will have the lowest concentration of DDT. Given the concentration in pond water is 0.04 ppm, the algae will have a concentration close to this value.
- **Fishes:** As primary consumers, fishes will consume algae and thus accumulate DDT. The concentration in fishes will be higher than in algae due to biomagnification.
- **Humans:** As the top consumers, humans will have the highest concentration of DDT because they consume fishes, which have already accumulated DDT from algae.

**Hint:** Think about how each organism accumulates DDT from the one below it in the food chain.

### Step 4: Sequence the DDT Concentrations
Based on the understanding of biomagnification:
- Algae will have the lowest concentration (approximately 0.04 ppm).
- Fishes will have a moderate concentration, higher than algae.
- Humans will have the highest concentration.

Thus, the correct sequence of DDT concentration in the food chain is:
1. Algae: Lowest concentration
2. Fishes: Moderate concentration
3. Humans: Highest concentration

**Hint:** The sequence should reflect the increasing concentration of DDT from algae to humans.

### Final Answer
The correct sequence of DDT concentration in the food chain is: **Algae < Fishes < Humans.**