Q.48 Which of the following are desired characteristics of birds?

1. Lacking urinary bladder
2. Females having one ovary
3. A few living birds have teeth
4. Colour vision
5. Endothermic

Choose the correct answer from the options given below:

1. A, B, C, D and E only
2. A, B and E only
3. A, B, D and E only
4. A, B, C and E only

   Bird characteristics MCQ tests avian adaptations for flight efficiency and survival, linking to prior genetics questions in your biology exam prep series.

   Correct Answer: C (A, B, D and E only)

   Modern birds evolved key traits for lightweight flight; option C misleads on teeth prevalence.

   Option A: Lacking Urinary Bladder – Correct

   Birds lack a urinary bladder to reduce weight for flight. They excrete semi-solid uric acid paste (white in droppings), conserving water unlike mammals’ liquid urine.

   Option B: Females Having One Ovary – Correct

   Most female birds have one functional ovary (left), the right regresses embryonically. This lightens body mass, aiding flight while supporting large yolky eggs.

   Option C: A Few Living Birds Have Teeth – Incorrect

   No living birds have teeth; all modern (Neornithes) species lost them, replaced by lightweight keratinous beaks. Extinct Archaeopteryx had teeth, but “living birds” excludes this.

   Option D: Colour Vision – Correct

   Birds possess tetrachromatic color vision (four cone types, including UV-sensitive), superior to human trichromatic vision. Oil droplets in cones enhance discrimination for foraging/mating.

   Option E: Endothermic – Correct

   Birds are endothermic (warm-blooded), maintaining high body temperature (~40°C) via high metabolism, feathers, and countercurrent heat exchange—essential for flight in varied climates.

   Exam Tip

   Bird characteristics MCQ hinges on flight optimizations: weight reduction (A,B), sensory upgrades (D), thermoregulation (E). Tooth loss defines modern Aves. Builds deuterostome theme from echinoderms.