Answer: Food chain.
Step-by-step explanation:
Food chain can be defined as the process by which energy flows through an ecosystem. The energy from the sun is trapped by plants and transferred from plants to animals.
The energy from the herbivores animals are transferred to carnivores and higher animals.
The flow of energy is unidirectional. It flows from the smaller organism to higher organisms.
Sun →producers→ primary consumers→ secondary consumers→ tertiary consumers
Example: Sun → plants→ rabbit →wolf →lion