(2) Absorption of water and fixation of Nitrogen Explanation: Branch roots are of two kinds: long-branching geotropic roots and shortbranching apogeotropic roots, which are referred to as coralloid because of their irregular, beady appearance. The coralloid roots contain symbiotic cyanobacteria (blue-green algae), which fix nitrogen. It also collects water and soil nutrients and store carbohydrates.