The most primitive type of stele is

Name the three basic tissue systems in flowering plants. List the tissues included under each system.

Vascular bundle with cambium is called

Assertion $:-$ Collenchyma forms the hypodermis of dicot stem.
Reason $:-$ This is the reason for flexibility of young dicotyledonous stems.

Grass leaves curl inwards during very dry weather. Select the most appropriate reason from the following:

In closed vascular bundles,the $..........$ is absent.