Statement 1: Limestone vegetation in tropical regions is luxuriant because of the heavy rainfall all year-round.

Explanation:
- Limestone is a type of sedimentary rock primarily composed of calcium carbonate. It is often found in tropical regions where there is abundant rainfall and warm temperatures.
- The heavy rainfall in tropical regions provides the necessary moisture for the growth of vegetation on limestone.
- The warm temperatures in these regions also contribute to the luxuriant growth of vegetation as they provide an optimal environment for plant growth.
- The high amount of rainfall ensures that there is a constant supply of water for plants, which is essential for their survival and growth.
- Additionally, the rainfall helps in the leaching of nutrients from the limestone, making them available for plant uptake.
- The combination of abundant rainfall, warm temperatures, and nutrient availability makes limestone vegetation in tropical regions lush and dense.

Statement 2: Settlements are scattered, and the population is often sparse.

Explanation:
- In many tropical regions, settlements are often scattered and the population is sparse.
- This is primarily due to the geographical features and the characteristics of the tropical environment.
- Tropical regions often have dense forests, rugged terrains, and a lack of infrastructure, which makes it difficult for large-scale settlements to flourish.
- The dense forests and rugged terrains create barriers to transportation and communication, making it challenging to establish and maintain settlements.
- The lack of infrastructure, such as roads, electricity, and water supply, further hinders the development of large settlements in tropical regions.
- Moreover, the tropical climate with its high temperatures and high humidity can be challenging for human habitation, leading to a preference for more scattered settlements.
- The sparse population in tropical regions is also influenced by factors such as limited economic opportunities, lack of basic amenities, and the presence of diseases endemic to the area.
- However, it is worth noting that there are exceptions to this general trend, and some tropical regions may have densely populated settlements, particularly in areas with better infrastructure and economic opportunities.

Conclusion:
- Both statements are correct.
- Statement 1 explains the luxuriant growth of vegetation in tropical regions with limestone due to heavy rainfall and favorable temperatures.
- Statement 2 highlights the scattered nature of settlements and sparse population in tropical regions due to geographical features, lack of infrastructure, and challenging climatic conditions.