In a swampy marshland, there can be frogs, turtles, snakes, alligators. cattail plants, and papyrus. If an ecologist studies the entire marshland to
understand the type of environment it provides and how the organisms
within it interact and survive as well as the various resources and minerals
the marshland provides, they are studying ecology at what level?

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.