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Carrying capacity of an ecosystem is the defined as the largest population that it can sustain indefinitely with the available resources. Biologists also refer to carrying capacity as the “maximum load”. Carrying capacity has factors it depends on. These are the many abiotic and biotic factors in the ecosystem and some are more obvious than others. The most obvious being, the availability of the basic needs of organisms which make up the different ecosystems. Some of these are food, water and shelter in which dictate how many individuals the ecosystem can sustain.
Answer: Possession of Valves
Explanation: Veins possess valves which ensures that blood flows in only one direction. Valves helps blood to flow back to the heart against gravitational force.
Arteries don't have valves because the pressure originating from the heart is capable of causing the blood to flow in one direction.
