निम्नलिखित में से किस भारतीय राज्य में काली मिट्टी (रेगुर मिट्टी) व्यापक रूप से पाई जाती है?

Which specific soil type is widely utilized for manufacturing bricks due to its unique characteristic of hardening when exposed to air?

What is the primary cause for the characteristic red color found in Red and Yellow soils?

Which specific type of soil is characterized by its heavy nature, dark color, and high organic matter content (up to 40-50%)?