Most of animals at present obtain their free energy from

Options

A. reduction of organic molecules
B. oxidation of organic molecules
C. light through photosynthesis
D. electricity and coal

Answer

**Step-by-Step Solution:**

1. **Understanding Energy Sources for Animals:**
- Animals require energy to perform various biological functions. The primary source of this energy is through metabolic processes.

2. **Identifying the Process of Energy Acquisition:**
- The main process through which animals obtain energy is respiration. This process occurs in every cell of the animal's body.

3. **Role of Organic Molecules:**
- Organic molecules, such as glucose, are crucial for respiration. These molecules are the substrates that are broken down to release energy.

4. **Oxidation of Organic Molecules:**
- During respiration, these organic molecules undergo oxidation. Oxidation is a chemical reaction where electrons are removed from the molecules, resulting in the release of energy.

5. **Energy Release:**
- The energy released during the oxidation of organic molecules is what animals use to fuel their activities, such as movement, growth, and reproduction.

6. **Conclusion:**
- Therefore, the correct answer to the question is that most animals at present obtain their free energy from the oxidation of organic molecules.

**Final Answer:**
Most animals at present obtain their free energy from the oxidation of organic molecules.

---