Answer:
Tributary, River,River System
Explanation:
Tributary is smaller because it is like a smaller river running into a larger one. River System is largest because this is all of the rivers in one.
Answer:
The third line of defence against pathogenic invasion is the adaptive immune response, which has two key qualities: It is specific (it can differentiate between specific microorganisms and respond accordingly) It is adaptive (it can produce a heightened response upon re-exposure - in other words, it has memory)
Explanation:
The answer is; 1
Most of the photosynthetic organisms are located in the epipelagic zone of the oceans where sunlight can penetrate before diffusing and becoming too weak to support photosynthesis. The epipelagic zone is filled with plankton. When this plantkon die, they begin to sink slowly to the bottom of the ocean. These plankton are food for small fish. These small fish are food for bigger fishes. This is how an ecosystem is sustained in the deep dark oceans.
The resistance increases then quickly stabilizes!
Nitrogen fixation is the process by which nitrogen is taken from its relatively inert molecular form (N2) in the atmosphere and converted into nitrogen compounds useful for other chemical processes (such as, notably, ammonia, nitrate and nitrogen dioxide).
Nitrogen fixation is performed naturally by certain types of anaerobic bacteria. Legumes such as clover contain symbiotic bacteria of this type within nodules in their root systems, producing nitrogen compounds that help to fertilize the soil. See George Washington Carver.
Nitrogen can also be artificially fixed for use as fertilizer or in other industrial processes. The most popular method is by the Haber process. Artificial fertilizer production has achieved such scale that it is now the largest source of fixed nitrogen in the Earth's ecosystem.
(This is the definition from the http://encyclopedia.kids.net.au/page/ni/Nitrogen_fixation website)
