Who proposed 5-kingdom classification ?

Explanation

**Step-by-Step Solution:**

1. **Understanding the Classification System**: The question asks about the 5-kingdom classification system, which is a way to categorize living organisms based on their characteristics.

2. **Identifying the Five Kingdoms**: The five kingdoms in this classification are:
- **Monera**: This kingdom includes prokaryotic organisms, primarily bacteria.
- **Protista**: This kingdom consists of eukaryotic unicellular organisms, such as amoeba.
- **Fungi**: This kingdom includes eukaryotic organisms that are heterotrophic, meaning they obtain their food from other sources.
- **Plantae**: This kingdom consists of eukaryotic organisms that are autotrophic, meaning they can produce their own food through photosynthesis.
- **Animalia**: This kingdom includes eukaryotic organisms that are heterotrophic and consume other organisms for nutrition.

3. **Identifying the Proposer**: The 5-kingdom classification was proposed by Robert H. Whittaker.

4. **Year of Proposal**: Robert H. Whittaker introduced this classification system in the year 1969.

5. **Final Answer**: Therefore, the answer to the question "Who proposed the 5-kingdom classification?" is Robert H. Whittaker.

---