Humus is composed of decomposed organic matter that has undergone multiple cycles of breakdown and synthesis. Humic substances are a group of highly acidic, yellow to black colored, high molecular weight compounds __________________, which can be isolated through various extraction methods:
Explanation
Humic substances include Hymatomelanic acid and Humin, as well as Humic acid and Fulvic acid. Therefore, both sets of compounds (A and B) are part of the humic substances group.