Staggered joints are generally provided on curves because they help to reduce the impact of wheel loads and improve the stability of the track.

**Explanation:**

Staggered joints refer to the arrangement of rail joints on a track where the joints of adjacent rails are not aligned. Instead, they are offset from each other by a certain distance. This offset or staggering helps to distribute the wheel loads more evenly along the track, particularly on curves.

- **Reducing Wheel Loads on Curves:**
On curves, the outer rail experiences higher wheel loads due to the centrifugal force acting on the trains. This increased loading can lead to accelerated wear and tear and even derailment if not properly managed. Staggered joints help to mitigate this issue by distributing the wheel loads more evenly between the rails. By offsetting the joints, the wheels encounter a smoother transition from one rail to another, reducing the impact on the outer rail.

- **Improving Stability:**
Staggered joints also contribute to the overall stability of the track on curves. The offset arrangement helps to minimize the abrupt changes in rail alignment, which can cause lateral forces and induce track instability. By providing staggered joints, the track structure becomes more flexible and can better accommodate the dynamic forces exerted by the moving trains on curves.

- **Other Rail Sections:**
While it is true that staggered joints can also be used when two different rail sections are required to be joined, this is not the primary reason for their provision. The primary purpose of staggered joints is to improve track stability and reduce the impact of wheel loads on curves.

In conclusion, staggered joints are generally provided on curves to reduce wheel loads and improve stability. While they can also be used when different rail sections need to be joined, this is not their main purpose. Staggered joints play a crucial role in maintaining the integrity and safety of the railway track system, particularly on curved sections.