How do the various leaf modifications help plants?

What is the epidermal cell modification in plants which prevents water loss?

Highlight any four areas where genetic modification of plants has been useful.

How is the mycorrhizal association helpful in absorption of water and minerals in plants?

Describe the various types of placentations found in flowering plants.

If one wants to find minerals and in the form they are mobilised in the plant, how will an analysis of the exudate help ?