A. Fill-in the missing word to complete the sentence. 1.____________ ​is an important interaction which is commonly observed in an ecosystem. Some organisms emerge on top of the competition while those who lose are left to die.  2.For animals, there is an eat-and-be-eaten relationship. The animals which eat or hunt for another animal is called the____________ ​ ​. 3.The animal which is eaten is called the ​____________​.  4.A ​____________ ​is one-directional model of feeding relationships in an ecosystem.  5.A ​____________, on​ the other hand, shows interconnected food chains. Looking closely, these models show the how energy flows from one organism to the next within an ecosystem.  6.An interaction where one organism of a certain species harms an organism of another species to benefit from the relationship is called ____________​.  7.The organism that harms and benefits from parasitism is called a ​____________. 8. There is another symbiotic relationship wherein an organism of a species benefits without affecting another organism of a different species. This kind of relationship is called ​____________.  9. Another kind of symbiotic relationship is called ____________​. There is mutualism if two organisms from different species benefit from each other.  ​10.____________ ​is the term used to describe the organism which is harmed.  11.The ____________is the third layer of a tropical rainforest. It is a thick layer composed of the leaves of plants or trees.  12.The topmost layer is called the____________. 13.The bottom part of the forest is called the ____________. There are only a few plants that can grow on it. 14.The____________ is where tree trunks, shrubs, and vines can be found. In this layer are large animals such as leopards, wild boars, and deer.  15.An ​___________ is an area where freshwater from rivers merges with salt water of the sea.   B. Briefly answer each part of the test.  3 points each 1.     What will happen in organisms if they do not interact with one another? 2.     What will happen to the community if there is no predation?  3.What differentiates a rainforest from other terrestrial ecosystems? ​