The correct answer is option 'D': "It perspires a lot to keep the body cool."

Explanation:
Camels are well-adapted to survive in the harsh desert conditions. They have several adaptations that help them thrive in such extreme environments. Let's go through the given options and understand why option 'D' is not an adaptation of camels for desert conditions.

1) It excretes very little urine and dry dung:
- Camels have the ability to conserve water by excreting very little urine. This adaptation helps them retain as much water as possible in their bodies, which is crucial in arid environments where water scarcity is a major issue. Additionally, their dung is dry, which further helps them conserve water.

2) Its feet are broad with paddy soles:
- Camels have broad, padded feet that enable them to walk on the hot desert sand without sinking. This adaptation helps distribute their weight over a larger surface area, preventing them from sinking into the soft sand and facilitating better traction.

3) It has a hump that stores fat:
- One of the most distinctive features of camels is their hump. The hump is not filled with water, as commonly believed, but with fat reserves. Camels can metabolize the stored fat in their humps to produce energy and water when food and water sources are scarce. This adaptation allows them to survive for long periods without food or water in the desert.

4) It perspires a lot to keep the body cool:
- This statement is incorrect. Camels do not perspire a lot to keep their bodies cool. In fact, they have a unique adaptation that helps them conserve water by minimizing sweat production. Unlike other animals, camels have a low rate of perspiration, which reduces water loss through sweating. This adaptation helps them survive in arid conditions where water availability is limited.

In conclusion, option 'D' is not an adaptation of camels for desert conditions because camels do not perspire a lot to keep their bodies cool. Instead, they have special mechanisms to conserve water and minimize sweat production.