Question

Ultimate source of energy for living beings is
A. Carbohydrates
B. Fats
C. Sunlight
D. ATP

Answer 1

A food chain is the linear network of links in a food chain pyramid or food web, where it generally starts with plants which are called as primary producers and they end at the apex predators, and it also shows how the organisms are related with each other by the food they eat, and in this food Chain Link, energy is transferred from one level to another level.

Complete answer:
The organisms in the ecosystem are placed in the food chain, based on the food they eat, they are classified into a different trophic level, Mainly food web is classified into five trophic levels
In level 1: consists of all green plants and algae, they are called producers, as they prepare food by themselves by a process called photosynthesis. And the energy for photosynthesis is obtained from
Level 2: The organisms in this level depend on level 1 that is plants, algae, hence this is called primary consumers and also herbivores, where they eat only plants and algae for their energy. Example: rabbits, cows, goats
Level 3: The organisms which eat only herbivores for their energy, where this is called secondary consumers or carnivores. Example: lion, fox rats
Level 4: Animals in this level are called tertiary consumers; they include carnivores (level 3 animals) and omnivores which means eat both plants and animals.
Level 5: It is the last trophic level where they prey on all levels and always be at the top of the food chain, so they are called apex predators. So level 5 organisms have come on top of the food chain as there are no predators for themselves.

So, the correct answer is option C.

Note: In the earth, plants are the only organisms which can prepare there own food, so they are considered as primary producers, and plants depend on sunlight for this process, where it converts the light energy to chemical energy and form the food, which energy produced by plants are move to other trophic levels, so the ultimate source energy for all living beings is sunlight.