Question

Most energy saving mode of excretion is________.

• A. ammonotelism
• B. ureotelism
• C. uricotelism
• D. guanotelism

Hint:

Energy vs Water trade-off: Ammonia = least energy, most water; Uric acid = most energy, least water.

Answer 1

The Correct Option is A

Concept:
Excretion of nitrogenous wastes occurs in different forms depending on the organism and habitat. The major types are:
• Ammonotelism → Excretion of ammonia
• Ureotelism → Excretion of urea
• Uricotelism → Excretion of uric acid These differ in terms of toxicity, water requirement, and energy consumption.

Step 1: Understand energy requirement of each type.
• Ammonia → Highly toxic but requires least energy to produce \checkmark
• Urea → Less toxic, requires moderate energy
• Uric acid → Least toxic, requires maximum energy

Step 2: Interpret “most energy saving”. “Energy saving” means the process that consumes the least metabolic energy. Ammonia is directly formed from amino acid deamination and does not require complex conversion.

Step 3: Analyze the options.
• (A) Ammonotelism → Least energy required \checkmark
• (B) Ureotelism → Requires energy for urea synthesis $\times$
• (C) Uricotelism → Highest energy consumption $\times$
• (D) Guanotelism → Not a standard major category $\times$

Step 4: Conclusion. Thus, the most energy-saving mode of excretion is: \[ \text{Ammonotelism} \]