Asafoetida $(Hing)$ is obtained from $Ferula$ $assa-foetida$. What is it?

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?

Roots are absent in which of the following plants?

Root hairs are found in:

Describe the modifications of roots for specific functions.

Velamen takes part in