Animals that eat plants get the energy stored in the plants and use it for things such as moving around. However, only a small fraction of the energy in the plants gets converted to useful energy for the animal. Most of the energy is lost to heat. How can this situation be used to support the idea of the law of conservation of energy?
A. A The amount of energy used by the animals, added to the amount of energy lost to heat, equals the amount of energy from the plants eaten by the animal.
B. B While some animals get their energy from plants, there are also many animals that get energy by eating other animals, and still other animals that eat both.
C. C All the energy lost to heat by animals provides the heat energy that plants need to live and grow, allowing them to make their own food.
D. D When plants and animals die, their energy goes into the soil, where growing plants can absorb it, turn it into food, then transfer this energy to animals.

A. A The amount of energy used by the animals, added to the amount of energy lost to heat, equals the amount of energy from the plants eaten by the animal.

Explanation:

The law of conservation of energy states that "energy can neither be created nor destroyed but can only be changed from one form to another". This means that during the energy transfer cycle, energy cannot be created or destroyed by any process, however, it can only be changed from one form to another via the different processes undergone by living organisms.

This question describes how animals get food needed for their life processes by feeding on plants. However, they (animals) make use of only a little fraction (about 10%) of the total energy in plants they feed on, because most of the energy (about 90%) is lost as heat when the plant undergoes metabolic activities.

This situation describes the law of conservation of energy in the statement that "The amount of energy used by the animals, added to the amount of energy lost to heat, equals the amount of energy from the plants eaten by the animal" because it shows that energy cannot be created neither can it be lost, hence, the sum of the energy that was converted to heat energy by plants and the energy utilized by the animal will give the total amount of energy initially present in the plant before the animal fed on it.