Q1. [1] medium thorough-understanding
Which of the following best explains why Spirogyra, a multicellular organism, can reproduce by fragmentation while most other multicellular organisms cannot?
(A) Spirogyra reproduces faster than other multicellular organisms.
(B) Each cell of Spirogyra is undifferentiated and capable of independent survival and growth.
(C) Spirogyra lives in water, which provides the physical force needed to break it apart.
(D) Spirogyra lacks a nucleus, so its cells can divide without any signal.
- A Spirogyra produces spores that can survive harsh conditions.
- B Spirogyra lacks specialised tissues and organs, so any fragment contains all it needs to grow into a new individual.
- C Spirogyra undergoes meiosis before breaking into fragments, ensuring each piece has the correct chromosome number.
- D Spirogyra fragments only release germ-cells, which then develop into new filaments.
Generated by claude-sonnet-4-6 · 2026-06-26 01:04 · grounding rag
Model Answer
(B) Spirogyra lacks specialised tissues and organs, so any fragment contains all it needs to grow into a new individual.
Explanation
The textbook states that Spirogyra has a "relatively simple body organisation" with no specialised tissues or organs. Activity 7.4 asks students to check whether different tissues can be identified in Spirogyra — implying they cannot. Because its cells are undifferentiated, every fragment has the full capability to survive and grow. In contrast, complex multicellular organisms have cells organised into tissues and organs, making cell-by-cell fragmentation impractical. Examiners expect you to link the absence of specialisation to the ability to reproduce by fragmentation.