Which types of species tend to dominate river ecosystems? How do conditions between fast-moving 'headwaters' (or sources) of rivers differ from slow-moving 'mouths' of rivers? Where are the majority of producers in a lake located? Where would you expect to find the largest food webs - oligotrophic, mesotrophic, or eutrophic lakes? Explain. What characteristic defines a wetlands? Why are wetlands so ecologically productive, and what valuable ecosystem services do they provide to humans? Where are coral reefs generally found, how are they built, and why are they under heavy threat from bleaching? Do the vast open oceans areas deeper than ~200 meters and away from coastlines support much life? Explain

Answers with Explanation:

Q1) In faster moving rivers, salmon species dominate. In slower moving rivers, catfish dominate.

Q2) Fast moving rivers have high oxygen levels due to the rapid mixture of water and air. Slow moving rivers experience less mixing of air and water, decreasing their oxygen levels.

Q3) The majority of producers are found at the littoral zone. This is because it is shallow and allows easy penetration of light for photosynthesis.

Q4) Eutrophic lakes, this is due to their high level of productivity.

Q5) The wetlands are biomes that are submerged or saturated by water for at least part of each year, but shallow enough to support vegetation.

Q6) The wetlands are ecologically effective as they take in large amounts of rainwater and release it slowly, helps to prevent droughts , filter pollutants, and recharge the ground with clean water.

Q7) The coral reefs are found in warm, shallow waters beyond the shoreline. They're built by secreting a layer of limestone to form their external skeleton. They're under heavy threat of bleaching due to lower ocean pH and higher water temperatures.

Q8) The vast open oceans areas deeper than 200 meters and away from coastlines doesn't support much life due to decrease in light intensity for photosynthesis and oxygen levels. These zones includes: mesopelagic zone, bathypelagic zone and abyssal zone.

the correct answer is:

a population changes in response to a change in the environment.