Answer: True
A food chain is a linear sequence of supply or transfer of food and energy when one organism is consumed by another in an ecosystem. The energy being transferred to different organisms can be studied on the basis of energy pyramid in which energy is distributed among organisms in subsequent trophic levels. At the base level, the producers or plants obtain energy from sun which they utilize to produce food or biomass energy. The biomass energy from plants is transferred to primary consumers or herbivores. The primary consumers are eaten up by secondary consumers. The secondary consumers are eaten up by tertiary consumers.
This can be concluded that the initial source of energy being distributed to all trophic levels in food chain is originated from sun. Therefore, the statement "In an ecosystem, energy that flows to tertiary consumers ultimately originates from the sun" is true.
