In which of the following animals is respiration carried out largely through the skin in addition to other organs, especially when the animal is in water?

Introduction / Context:
This biology based question tests your understanding of different modes of respiration in animals. While most vertebrates rely mainly on lungs or gills, some animals have additional adaptations that allow them to exchange gases through their skin. Amphibians are a classic example of this dual respiratory strategy. Recognising which animal uses its skin for respiration helps clarify basic zoology concepts.

Given Data / Assumptions:

• The focus is on respiration through the skin, also called cutaneous respiration.
• The options are different aquatic or semi aquatic animals: flying fish, sea horse, frog, chameleon and lizard.
• We assume the question is about the best known example where skin plays a major role in gas exchange.
• The animal should be able to carry out significant respiration through moist skin, especially in water.

Concept / Approach:
Amphibians like frogs have thin, moist and well vascularised skin that allows gases to diffuse directly into the blood. This is called cutaneous respiration and it can be very important when the frog is underwater or during hibernation. Although frogs also possess lungs, their skin is a crucial respiratory organ. In contrast, flying fish and sea horses are true fishes that rely on gills, while reptiles like chameleons and lizards use lungs and have dry, scaly skin not suited for gas exchange.

Step-by-Step Solution:
Step 1: Identify the class to which each option belongs: fish, amphibian or reptile. Step 2: Recall that amphibians, especially frogs, are often cited in textbooks as animals that respire not only through lungs but also through their skin. Step 3: Note that flying fish and sea horses are fishes with scales and gills, designed for gill based respiration rather than cutaneous respiration. Step 4: Remember that chameleons and other lizards are reptiles with dry scaly skin, which is unsuitable for significant gas exchange. Step 5: Based on this comparison, choose frog as the animal that respires through the skin.

Verification / Alternative check:
Standard biology textbooks explain that frogs can perform cutaneous respiration especially during their aquatic phase or when submerged for long periods. Diagrams show blood vessels close to the skin surface, which enhance gas exchange. Exam explanations frequently use frogs as examples when introducing amphibian respiration, confirming that the frog is the correct answer when skin based breathing is mentioned in such questions.

Why Other Options Are Wrong:
Flying fish are normal bony fishes that use gills for respiration; their brief gliding above water does not involve skin based gas exchange.
Sea horse is a fish with gills and does not use its skin as a major respiratory organ.
Chameleon is a reptile with thick, scaly skin, which prevents efficient diffusion of gases and therefore does not support cutaneous respiration.
Lizard has a similar reptilian body covering and depends on lungs rather than skin for respiration.

Common Pitfalls:
A common error is to assume that any animal living in water must breathe through its skin. Many students also confuse amphibians and reptiles because both can spend time on land. To avoid mistakes, remember that amphibians like frogs have moist skin suitable for gas exchange, whereas reptiles have dry scales that protect against water loss but prevent significant skin breathing. Keeping this distinction clear will help you answer similar questions accurately.

Final Answer:
Among the given options, the animal in which respiration is carried out significantly through the skin is the frog.