Ozone is produced naturally in the stratosphere. But this "good" ozone is gradually being destroyed by man-made chemicals referred to as ozone-depleting substances (ODS), including chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halons, methyl bromide, carbon tetrachloride, and methyl chloroform. These substances were formerly used and sometimes still are used in coolants, foaming agents, fire extinguishers, solvents, pesticides, and aerosol propellants. Once released into the air these ozone-depleting substances degrade very slowly. In fact, they can remain intact for years as they move through the troposphere until they reach the stratosphere. There they are broken down by the intensity of the sun's UV rays and release chlorine and bromine molecules, which destroy the "good" ozone. Scientists estimate that one chlorine atom can destroy 100,000 "good" ozone molecules.
The salt water is denser than the fresh water so that the things can float over it as more will be the dense water the egg will be more easily floating
hope it helps
The answer would be survival of the fittest.
This metaphor, "<em>survival of the fittest</em>," was used by Herbert Spencer to explain <em>natural selection. </em>It is sometimes also referred to as the survival for existence. This phrase came from the Dawinian theory of evolution where he explains that all species are capable of producing many offsprings. However, the survival of those offsprings depends on their ability to adapt to the risks and opportunities of the external environment.
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</em>This relates to your scenario in the sense that fish lay a lot of eggs in the beginning but not all of them would live to achieve maturity. This is because even as eggs, they have many predators and are exposed to other elements. The threat pushes on even if they are able to hatch and grow up.
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Answer:
Agricultural fertilizers are one of the main human causes of eutrophication. Fertilizers, used in farming to make soil more fertile, contain nitrogen and phosphorus. The use, or overuse, of fertilizers can cause these nutrients to runoff of the farmer's field and enter waterways. Eutrophication can have serious effects, like algal blooms that block light from getting into the water and harm the plants and animals that need it. If there's enough overgrowth of algae, it can prevent oxygen from getting into the water, making it hypoxic and creating a dead zone where no organisms can survive.
The following is a list of methods that can be used to control eutrophication:
planting vegetation along streambeds to slow erosion and absorb nutrients.
controlling application amount and timing of fertilizer.
controlling runoff from feedlots.
The best, easiest, and most efficient way to prevent eutrophication is by preventing excess nutrients from reaching water bodies. This can be done in a number of ways, the simplest of which is just being aware of the chemicals and fertilizers that we are using.
