Question

Which of the following are primary consumers in a food chain ?

• A. Carnivores
• B. Parasites
• C. Predators
• D. Herbivores

Hint:

• Trophic Level Association: itemize

• Producers \(\rightarrow\) Autotrophs (\(T_1\))

• Primary Consumers \(\rightarrow\) Herbivores (\(T_2\))

• Secondary Consumers \(\rightarrow\) Primary Carnivores (\(T_3\))

• Tertiary Consumers \(\rightarrow\) Secondary/Top Carnivores (\(T_4\))
10% Law of Energy Transfer: Only about 10% of the energy available at one trophic level is transferred to the next level. The remaining 90% is lost primarily as metabolic heat during respiration and through waste. itemize

Answer 1

The Correct Option is D

Step 1: Read the question.
We need the group that acts as primary consumers in a food chain.
Step 2: Recall trophic levels.
Producers (green plants) are the first level. Primary consumers are the second level and feed directly on producers.
Step 3: Define primary consumers.
Since they eat only producers (plants, algae, phytoplankton), primary consumers are herbivores, for example cows, deer, rabbits, and zooplankton.
Step 4: Test carnivores and predators.
Carnivores and predators eat other animals, so they sit at the third level or higher as secondary or tertiary consumers, not primary.
Step 5: Test parasites.
Parasites have no fixed trophic level because it depends on their host, so they do not define the primary consumer level.
Step 6: Conclude.
The plant-eating herbivores are the primary consumers, which is option (4).
\[ \boxed{\text{Herbivores}} \]