Correct Option
The correct option is (c) 1 and 3 only.
Explanation
The Cell Theory is a fundamental principle in biology which establishes the cell as the structural and functional unit of all living organisms. It provides the basis for understanding the organization of life forms.
Statement-wise Analysis
- Statement 1 is Correct: The classical Cell Theory was formulated by two scientists: Matthias Schleiden (1838), a botanist, and Theodore Schwann (1839), a zoologist. They proposed that all plants and animals are composed of cells and products of cells.
- Statement 2 is Incorrect: The Cell Theory explicitly states that the cell is the basic unit of life. Viruses are considered exceptions to the Cell Theory because they are acellular (lacking cellular organization like cytoplasm and organelles) and cannot reproduce independently without a host.
- Statement 3 is Correct: The original theory by Schleiden and Schwann failed to explain how new cells were formed. In 1855, Rudolf Virchow expanded the theory by adding the concept of "Omnis cellula-e cellula", which means that all cells arise from pre-existing cells.
Key Takeaway: Modern Cell Theory encompasses three main tenets: all living organisms are made of cells, the cell is the fundamental unit of life, and all cells come from pre-existing cells. Viruses are acellular and do not fit into this theory.