All these statements about trophic levels and ecosystems are false except

Options

A. Trophic level represents a functional level, not a species as such
B. A given species never occupies more than one trophic level in the same ecosystem at the same time
C. In most ecosystems , producers are less in number and biomass than the herbivorous
D. Pyramid of energy can never be upright .

Answer

To solve the question, we need to identify which statement about trophic levels and ecosystems is true, while the others are false. Let's analyze each option step by step.

### Step 1: Understand the concept of trophic levels
Trophic levels represent the position of organisms in a food chain or food web, based on their feeding relationships. They are categorized into producers, primary consumers, secondary consumers, and so on.

**Hint:** Remember that trophic levels are about functional roles in ecosystems, not specific species.

### Step 2: Evaluate the first option
The first statement claims that "trophic levels represent a functional level, not a species as such." This statement is true because trophic levels categorize organisms based on their role in the ecosystem, such as producers or consumers, rather than their specific species.

**Hint:** Focus on the definition of trophic levels and their functional significance.

### Step 3: Evaluate the second option
The second statement says, "A given species never occupies more than one trophic level in the same ecosystem at the same time." This statement is false because some species can occupy multiple trophic levels depending on their diet and life stage (e.g., a species can be a herbivore at one stage and a carnivore at another).

**Hint:** Consider how species can change their feeding habits over their life cycle.

### Step 4: Evaluate the third option
The third statement claims, "In most ecosystems, producers are less in number and biomass than the herbivores." This statement is also false. Typically, producers (like plants) are more abundant and have greater biomass than herbivores because they form the base of the food web.

**Hint:** Think about the energy flow in ecosystems and the base of the food chain.

### Step 5: Evaluate the fourth option
The fourth statement says, "Pyramid of energy can never be upright." This statement is false. The pyramid of energy is always upright because energy decreases as it moves up trophic levels due to energy loss at each transfer (according to the second law of thermodynamics).

**Hint:** Remember how energy transfer works in ecosystems and the typical shape of energy pyramids.

### Conclusion
After evaluating all the options, the only true statement is the first one: "trophic levels represent a functional level, not a species as such." Therefore, the correct answer is option 1.

**Final Answer:** Option 1 is correct.