which of the following statements about the global phosphoroud cycle is true? a. some phosphorous applied to crops as fertilizer leaves the terrestrial subsystem  b. the bulk of earths phosphorous is found in deep ocean waters c. fertilizers have decreased phosphorous availability in terrestrial ecosystems d. the mining of phosphorous ore is an insignificant source of phosphorous for fertilizers

- Situation 3: Irrigation was used when soil moisture dropped to 1%. a. If irrigation begins when soil moisture reaches 49%, what application of nitrogen will result in the lowest percentage of protein in wheat grain? b. If irrigation begins when soil moisture reaches 34%, what application of nitrogen will result in the same protein content of wheat grain as begin- ning irrigation when soil moisture reaches 1%? c. If you irrigate when soil moisture reaches 34%, how much nitrogen should you apply to achieve a 13% protein content in wheat grain? d. Does Figure 1.45 indicate that, for nitrogen levels at 45 pounds per acre or higher, increased protein content in wheat grain is associated with higher or lower soil moisture? 14 1% 13+ 34% 12 49% 11+ 10- 6, 40 60 80 100 120 140 Nitrogen FIGURE 1.45 Protein content versus availability of nitrogen % Protein 20

AP Environmental Science Primary Productivity Problems   Net Primary Productivity efficiency can be calculated for terrestrial producers when values for insolation energy, respiration loss and gross productivity are known. Use the equations below to answer the following problems:   Net Primary Productivity = Gross Productivity – Respiration Loss   Efficiency = .          NPP           . X 100                      Insolation Energy   In a rice paddy in Southeast Asia, the insolation energy is 6,000,000 calories/m2/day. The gross productivity of the rice is 0.012 grams/cm2/day, and the respiration loss is 20 percent. One gram of rice is equivalent to 1000 calories.   Calculate the net primary productivity of the rice.               Find the efficiency of photosynthesis by the rice.   Could you mostly help me set it up and find it? So I can learn how to do it.

what organism would be most affected  by a blightr that eliminates all plant material from an ecosystem? a. hetertrophic marine decomposers  b.  hetertrophic soil decomposers  c. chemolithoautotrophs  d. oxygenic microbial phototreophs  e.anoxygenic microbial phototreophs