A simple, single path of energy flow through an ecosystem is called a food:

• A. chain
• B. pyramid
• C. cycle
• D. web

Answer: (A)

Verified step by step guidance

1. Step 1: Begin by understanding the concept of energy flow in an ecosystem. Energy flows through organisms in a sequence, starting from producers (like plants) to consumers (like herbivores and carnivores). This sequence is often represented in specific models.
2. Step 2: Review the definitions of the given options: 'chain,' 'pyramid,' 'cycle,' and 'web.' A food chain represents a linear sequence of energy transfer, a food pyramid shows energy levels in a hierarchical structure, a food cycle refers to nutrient recycling, and a food web represents interconnected food chains.
3. Step 3: Focus on the term 'single path' mentioned in the problem. This indicates a straightforward, linear flow of energy, which aligns with the definition of a food chain rather than the other options.
4. Step 4: Eliminate incorrect options based on their definitions. A food pyramid is hierarchical, a food cycle involves nutrient recycling, and a food web is complex and interconnected. None of these represent a single path of energy flow.
5. Step 5: Conclude that the correct term for a simple, single path of energy flow through an ecosystem is 'food chain,' as it directly matches the description provided in the problem.