Which factor is a density-dependent limiting factor on the population of a species?
a- predation
b- unusual weather
c- natural disasters
d- seasonal variation

The correct answer is A. Predation

Explanation:

In biology, a limiting factor refers to a factor that limits the growth of a population preserving balance in ecosystems. Factors can be a density-dependent if they are directly related to the density of the population or independent if they are not related to the density of the population. From the options given, predation is the only density-dependent factor because this directly depends on the density of the population, for example, more animals to predate mean more predators and a decrease in the population of the prey, and, in the same way, few preys available leads to few predators.

4.) metal

"-the movement of carbon from the nonliving environment into living things and back to the environment

-carbon is the essential component of proteins, fats, and carbohydrates (which make up all organisms)

-carbon exists in air, water, and living organisms

-producers convert carbon dioxide in the atmosphere into carbohydrates during photosynthesis

-bacteria in the atmosphere cycles through the system in filtration units

-in cellular respiration, carbon is released back into the atmosphere as carbon dioxide

-some carbon is stored in limestone (forming one of the largest "carbon sinks" on earth)

-largest carbon reservoir on earth= limestone

-carbon stored in the bodies of organisms as fat, oils, or other molecules may be released into the soil or air when the organism dies

-this may form deposits of coal, oil, or natural gas (fossil fuels, which increased the atmospheric carbon dioxide)

-fossil fuels store carbon left over from bodies of organisms that died millions of years ago

-they are located in the surface of earth, deep within the earth and beneath the ocean floor."    

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