The correct answer is option 1, Viruses. Viruses are considered the most adaptable and versatile micro-organisms. While they are not technically considered living organisms, they have the ability to adapt and evolve rapidly to their environment. Viruses can infect a wide range of hosts, including animals, plants, and even other micro-organisms. They are known for their ability to mutate quickly, allowing them to evade the immune system and develop resistance to antiviral medications. Additionally, viruses can transfer genetic material between different species, which enhances their adaptability. This adaptability and versatility make viruses highly successful in surviving and spreading in various environments.