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UPSC Prelims 2003 · Environment · Species Watch
Consider the following statements: Which of these statements is/are correct?
- The common Blue green algae, Spirogyra and Ulothrix are found in both freshwater ponds and oceans.
- The chameleon can look ahead with one eye, and at the same time look behind with another.
- (a) Only 1
- (b) Only 2
- (c) Both 1 and 2
- (d) Neither 1 nor 2
Show the answer and explanation
Answer: (b) Only 2
Spirogyra and Ulothrix are mostly freshwater; chameleon eyes move independently.
Statement by statement
1. ✗ WRONG Blue-green algae live in both, but Spirogyra and Ulothrix are mostly freshwater algae of ponds and streams.
2. ✓ CORRECT A chameleon’s eyes move independently — it can look forward and backward at once.
The idea
Spirogyra and Ulothrix are green thread-like algae, mostly of still or slow fresh water; Spirogyra is the slimy “pond silk”. Some Ulothrix live in the sea. Blue-green algae (cyanobacteria) are a different group and live almost everywhere.
Fresh water: Spirogyra, Ulothrix, Chlamydomonas → Sea: seaweeds such as kelp and Sargassum → Both: blue-green algae
The trap
Statement 1 opens with a group that really is in both waters, then adds two that are mostly freshwater.
Also know
Each eye of a chameleon sits in a cone-shaped turret and swivels on its own, giving almost all-round vision. When it spots an insect, both eyes turn forward to judge the distance.
🔒 Spirogyra, Ulothrix = mostly freshwater. Chameleon = independent eye movement.