Which one of the following is oviparous ?

Options

A. Human being
B. Dog
C. Cow
D. Hen

Explanation

To determine which one of the following is oviparous, we need to understand the concept of oviparous animals and how they reproduce.

### Step-by-Step Solution:

1. **Define Oviparous**: Oviparous animals are those that lay eggs. The eggs develop outside the mother's body, and after a certain period, they hatch into young ones.

2. **Identify Characteristics**: Oviparous species typically include birds, reptiles, amphibians, and many fish. They lay eggs that contain the developing embryo.

3. **Contrast with Viviparous**: Viviparous animals give birth to live young. In these species, the embryo develops inside the mother's body and is nourished through a placenta or similar structure. Examples include humans, dogs, and cows.

4. **Examples of Oviparous Animals**: Common examples of oviparous animals include hens (chickens), turtles, and many species of fish.

5. **Select the Correct Answer**: From the options given, identify which animal is known to lay eggs. Based on the examples discussed, the hen is a clear example of an oviparous animal.

### Conclusion:
The answer to the question "Which one of the following is oviparous?" is **hen**.