Answer:
The mechanism is natural selection.
Explanation:
Natural selection is the mechanism that these air-breathing fishes have gone through to survive. This mechanism allows species to survive and reproduce due to differences in the phenotypes of every individual in the specie, throughout the time the heritable traits that every individual inherits changes according to the environment and the characteristics of its ancestors.
Rock cycle- the prices in which rocks undergo in the earths crust, involving igneous instruction, uplift, erosion, transportation, deposits as sedimentary rock.
Tectonic cycle- the movement of large portions of earths crust (plates) the driving forces that move these plates are a combination of events that occurs within the earth.
Water cycle- the path of all water followers as it moves around earth in different states, water vapor, ice, water...
Carbon cycle- series of processes by which carbon compounds are inverted in the environment involving the incorporation of carbon dioxide into living tissue by photosynthesis.
Nitrogen cycle- series of processes by which nitrogen and is compounds are introverted in the environment and living organisms.
Phosphorus cycle-biochemical cycle that describes the movement of phosphorus through the lithosphere, hydrosphere, and biosphere.
Cells are the basic unit of life and they are the 1st level of organization. The heart is the 3rd level. They are separated by 1 level, tissues.
Answer: "sexual dimorphism" .
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