What is the shape of a drop of water?

If the drop is small enough, it is a perfect sphere.
 A sphere is the geometrical shape that has the smallest surface area for its volume. The drop takes this shape because water molecules tend to stick to each other. So, when not confined by a container, and with nothing around it to distort its shape, a very tiny water drop is perfectly round like a ball because the water molecules are pulling inward toward each other. 

If the drop is larger like a raindrop in free-fall, it has a domed top and a semi-flattened bottom because as it falls it must push the air out of its way. That "upward" push of the air being displaced causes the falling drop to have a rather flattened bottom. 

Contrary to popular misconception, a free-falling raindrop is not shaped like a teardrop -- round on the bottom and pointy on top.

From:https://www.quora.com/When-a-water-drop-falls-does-it-form-a-circular-shape

Ichoose a as my answer

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.