Multiple choice

The excreta of lizards and birds contains a white component, which is chemically

  1. urea

  2. uric acid

  3. creatine

  4. precipitated calcium
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Birds and reptiles are uricotelic organisms, meaning they excrete nitrogenous waste primarily as uric acid. Uric acid is relatively non-toxic and can be concentrated to a white paste or solid, allowing these animals to conserve water - a critical adaptation for life in dry environments. Urea (mammals) and creatine are different nitrogenous compounds, while precipitated calcium is not involved in nitrogen excretion.

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