The xylem in the vein of the leaf does what

Xylem conducts water from the roots up to the leaves where it is used for photosynthesis 

The Xylem conducts water from the roots up to the leaves where it is used for photosynthesis. The xylem and phloem tissues are found together in all parts of a plant to form vascular bundles. These vascular bundles are visible in leaves asveins

Long term continuous groundwater monitoring, especially with warning systems and anthropic activity monitors

the glands which are associated with each description is given below:

pancreas - is an endocrine and exocrine gland that secretes juices with enzymes for digestion. salivary glands- with protection and digestion in the mouth. liver- secretes bile for digestion.   lachrymal glands - secrete tears to moisten eyes and protect them from particles and infection.   sweat gland -regulates water, salt, and temperature. oil glands - to form a protective barrier on the skin.   goblet cells - secrete mucus for protection.