Cow is an animal, it does not have feathers on its skin.

Introduction:
Feathers are a unique characteristic of birds that help them fly, regulate body temperature, and provide protection. However, not all animals have feathers on their skin. In this question, we are asked to identify the animal among the given options that does not have feathers on its skin.

Explanation:
Among the given options, the animal that does not have feathers on its skin is a cow (option C). Cows belong to the mammal group and have a different type of skin covering called hair. Let's discuss each option in detail:

a) Sparrow:
Sparrows are small birds that belong to the Passeridae family. They have feathers covering their entire body, which help them fly efficiently. Feathers maintain the bird's body temperature, provide insulation, and aid in flight.

b) Crow:
Crows are large black birds that belong to the Corvidae family. Like other birds, crows have feathers covering their body. Feathers provide various advantages to crows, such as efficient flight, protection, and insulation.

c) Cow:
Cows are domesticated mammals that belong to the Bovidae family. Unlike birds, cows do not have feathers on their skin. Instead, they have a different type of skin covering called hair. The hair on a cow's skin helps to regulate body temperature, protect against external elements, and provide sensory information.

d) Pigeon:
Pigeons are birds that belong to the Columbidae family. Similar to other birds, pigeons have feathers covering their entire body. Feathers play a vital role in their flight and provide insulation to maintain body temperature.

Conclusion:
Among the given options, the animal that does not have feathers on its skin is a cow (option C). Cows have hair on their skin, which serves similar functions to feathers in birds but is structurally different.