Lateral roots arise from

The calyptrogen of the root apex forms

Roots obtain oxygen from air in the soil for respiration. In the absence or deficiency of $O_{2}$,root growth is restricted or completely stopped. How do the plants growing in marsh lands or swamps obtain their $O_{2}$ required for respiration?

$Santalum$ $album$ is

Root cap is not found in

Root hairs occur in the zone of