DENDROLOGY

Detailed explanation-1: -Primary growth is a result of rapidly-dividing cells in the apical meristems at the shoot tip and root tip. Subsequent cell elongation also contributes to primary growth. The growth of shoots and roots during primary growth enables plants to continuously seek water (roots) or sunlight (shoots).

Detailed explanation-2: -Apical meristems give rise to the primary plant body and are responsible for the extension of the roots and shoots. Lateral meristems are known as secondary meristems because they are responsible for secondary growth, or increase in stem girth and thickness.

Detailed explanation-3: -Apical meristems at the tips of shoots and roots give rise to three primary meristems (protoderm, ground meristem, and procambium), which in turn produce the three tissue systems of the plant body.