$A$ vascular bundle in which the phloem is found on both sides of the xylem is called .....

The ground tissue system is equal to $...........$

Generally,the cells of the cortex lack $.....$.

$A$ vascular bundle is considered closed when:

Cystolith mineral crystals are found in:

$A$ student observed grass and $Hibiscus$ plants in his garden during noon. To his surprise,only the leaves of grass were found rolled inwards. The reason could be