In which one of the following groups do all the listed animals naturally have no teeth at all?

Introduction / Context:
This zoology question examines your understanding of basic anatomical features of different animal groups. Teeth are important structures in many vertebrates, but not all animals have them. Birds, for example, generally lack teeth and use beaks to handle food. Reptiles vary in this respect. Being able to identify a group in which all members naturally bear no teeth is a useful classification exercise for exams.

Given Data / Assumptions:

• The task is to find a group in which all animals are naturally toothless.
• The options combine birds, reptiles and mammals in different ways.
• We assume the question uses standard textbook knowledge about presence or absence of teeth.
• Animals that may have beaks but no true teeth are considered toothless in this context.

Concept / Approach:
Modern birds do not possess true teeth; instead, they have keratinous beaks adapted to their diet. Examples like peacock and ostrich therefore fit the category of toothless animals. Some reptiles like turtles and tortoises also have beak like structures and lack true teeth. In contrast, cows, owls, lorises, alligators and many other vertebrates do have teeth. Thus, we need to locate the option where every listed animal falls into the category of toothless birds or reptiles with beaks and no true teeth.

Step-by-Step Solution:
Step 1: Examine option A: peacock, ostrich and tortoise. Peacock and ostrich are birds and thus have beaks without teeth, while tortoise is a reptile with a horny beak rather than teeth. Step 2: Examine option B: turtle, kiwi and cow. Turtle and kiwi are toothless, but cow definitely has teeth, so the group fails the all toothless condition. Step 3: Examine option C: owl, loris and crow. Owl and crow are birds with beaks, but loris is a primate with teeth, so this group is not entirely toothless. Step 4: Examine option D: alligator, turtle and tortoise. Alligator has many sharp teeth, so this group also does not qualify. Step 5: Examine option E: snake, frog and pigeon. Snakes have teeth or fangs and frogs have small teeth on the upper jaw in many species, so this group also contains toothed animals. Therefore, only option A has three animals with no true teeth.

Verification / Alternative check:
School level biology explains clearly that modern birds lack teeth and instead have beaks. It also points out that turtles and tortoises possess sharp keratinous edges without true teeth. A quick mental check confirms that cows, lorises and alligators are all examples of animals with teeth, so any option containing them cannot be entirely toothless. This cross checking supports the choice of peacock, ostrich and tortoise as the correct group.

Why Other Options Are Wrong:
Turtle, kiwi and cow includes cow, which has well developed teeth to chew plant material.
Owl, loris and crow includes loris, a primate with teeth adapted for its omnivorous diet.
Alligator, turtle and tortoise includes alligator, a reptile with strong teeth for catching prey.
Snake, frog and pigeon includes snakes and many frogs that possess teeth or tooth like structures, so the group is not toothless.

Common Pitfalls:
A frequent mistake is to look only at birds in an option and assume all combinations of birds must be toothless without checking the entire group. Another pitfall is misunderstanding frogs and snakes as entirely toothless, when many species do have teeth or fangs. A systematic approach, checking each member of a group, ensures you choose the only option in which every animal naturally lacks true teeth.

Final Answer:
The group in which all animals naturally bear no teeth is peacock, ostrich and tortoise.