Question

Q4.20. Ecologists describe Earth's global biogeochemical cycles as closed. What does this mean? Earth as a whole is neither gaining nor losing significant amounts of any nutrient. Energy flowing through global cycles powers nutrient transformations within them. The total flux into each subsystem (such as the terrestrial subsystem) equals the total flux out. The size of each nutrient pool (e.g., terrestrial soils, ocean biota) is fixed within each cycle. Submit Q4.21. Which of the following statements about the global phosphorus cycle is true? Some phosphorus applied to crops as fertilizer leaves the terrestrial subsystem. The bulk of Earth's phosphorus is found in deep ocean waters. Fertilizers have decreased phosphorus availability in terrestrial ecosystems. The mining of phosphate ore is an insignificant source of phosphorus for fertilizers. Submit

Answer 1

of Earth's ay cles are closed as globas biogeochemical Cycles earth act as whole is neither gaining nos losing significant amounts of any putrient. It is erecycling in the form of cycle. Earth is open system in oregard to flow of energy. Energy Unidirectional way So flow in 1 correct. & incorrect energy bowlen transformation in unidirectional way 3 4 incorrecta 91) Option b correct The bulk of earth's phosphorous found in deep ocean water ocean sediment get weathered. as