Fill in the blanks: In older trees , the greater part of �a�.
Channel: Doubtnut
Date: 26/01/2020

Fill in the blanks: In older trees , the greater part of �a�. Is dark brown due to deposition of tannins, resins, oil, guns, aromatic substanceces and essential oil in the central layers of the stem. These substances make it hard durable and resistant to the attacks of microorganisms and insects .This region is called .. b ...