Question

The ultimate source of energy on earth for all living organisms is ______ .

Answer 1

Sun ; the ultimate source of energy:

1. Sun is the ultimate source of energy for all the organisms on earth.
2. The energy from the sun is directly utilized by some organisms and other organisms depend on these organisms for their energy requirement.
3. For instance, all the autotrophic organisms, also known as producers utilize sunlight to produce their food in the form of glucose.
4. These organisms store this food in the form of starch.
5. These plants are consumed by primary consumers i.e. herbivores to derive energy.
6. Then the secondary and tertiary consumers i.e. carnivores consume energy from primary consumers.

Final answer: The ultimate source of energy on earth for all living organisms is sun.