**Adaptations in Animals**

**Introduction:**
Adaptations are modifications or traits that help organisms survive and thrive in their specific environments. Different animals have different adaptations that enable them to meet the challenges of their habitats. In this question, we are asked to identify the animal that has the correct form of adaptation out of the given options. Let's analyze each option to find the correct answer.

**a) Camel: bristles on its feet:**
Camels have several adaptations that enable them to survive in the desert. However, bristles on their feet are not one of them. The bristles on a camel's feet are actually protective hairs that help prevent sand from entering their hooves, which is important for walking in sandy environments. Therefore, this adaptation is incorrect in the context of the question.

**b) Whale: blowholes in its head:**
Whales are marine mammals that have evolved to live in water. One of their most distinctive adaptations is the presence of blowholes in their heads. These blowholes are specialized nostrils that allow whales to breathe air at the water's surface without having to fully expose their bodies. This adaptation is crucial for their survival and is the correct answer to the question.

**c) Mudskipper: lungs for breathing:**
Mudskippers are unique fish that can survive out of water for extended periods of time. They have adapted to their muddy habitats by developing lungs, which allow them to breathe air. This adaptation is useful for mudskippers when they are in areas with low oxygen levels or when the water dries up. However, in the context of the question, this adaptation is incorrect as it does not match with the given animal.

**d) Birds: compact bones:**
Birds have a variety of adaptations that enable them to fly and live in different environments. One of these adaptations is having hollow or pneumatic bones. These bones are lightweight and filled with air sacs, which help reduce the bird's overall weight, making it easier for them to fly. Compact bones, on the other hand, are denser and heavier, and not a correct adaptation for birds.

**Conclusion:**
Out of the given options, the correct animal with the appropriate adaptation is the whale, which has blowholes in its head. This adaptation allows whales to breathe air at the water's surface, making it easier for them to survive in their marine environment.