Natural wetlands are lands which, due to geological or ecological factors, have a natural supply of watereither from tidal flows, flooding rivers, connections with groundwater, or because they are perched above aquifers or potholes.
Realize that many verbs can be both transitive and intransitive. An action verb with a direct object is transitive while an action verb with no direct object is intransitive. Some verbs, such as arrive, go, lie, sneeze, sit, and die, are always intransitive; it is impossible for a direct object to follow.
Should, have = auxiliary verbs; been = past participle; eating = present participle. A verb can have as many as four parts. When you form multipart verbs, you use a combination of auxiliary verbs and participles.