DENDROLOGY

Detailed explanation-1: -In primary succession, newly exposed or newly formed rock is colonized by living things for the first time. In secondary succession, an area previously occupied by living things is disturbed-disrupted-then recolonized following the disturbance.

Detailed explanation-2: -Primary succession begins when no plant life is present on the landscape, such as after a lava flow or glacial retreat. Over centuries, soil forms and deepens and successive communities of plants grow.

Detailed explanation-3: -Primary succession is ecological succession that begins in essentially lifeless areas, such as regions in which there is no soil or where the soil is incapable of sustaining life (because of recent lava flows, newly formed sand dunes, or rocks left from a retreating glacier).