Which meristeme is present at the base of the leaves
How does it help there?

Dear student,
Please find below the answer:

It is the Intercalary meristems that are found at the base of the stem or leaf internodes. They are a type of meristems that help in the elongation and development of plants in the nodes and internodes of stems and leaves. They assist the plant in its longitudinal growth of stems and leaves.

Hope this clears your doubt.
Regards.