Wheat:  Net sales of 80,600 metric tons for 2019/2020--a marketing-year low--were down 74 percent from the previous week and 87 percent from the prior 4-week average.   Corn: Net sales of 161,900 metric tons for 2019/2020--a marketing-year low-were down 70 percent from the previous week and 83 percent from the prior 4-week average.    Soybeans:  Net sales of 355,500 MT for 2019/2020 were up 8 percent from the previous week, but down 59 percent from the prior 4-week average.   Soybean Cake and Meal:  Net sales of 74,200 MT for 2019/2020--a marketing-year low--were down 22 percent from the previous week and 47 percent from the prior 4-week average.   Soybean Oil:  Net sales...