बांगर मिट्टी में कंकड़ ग्रंथियां पाई जाती हैं, जिनमें निम्नलिखित में से किसकी प्रचुरता होती 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%)?