Ecosystem services are required to rebalance natural systems that we have disturbed are economically valuable services provided by natural systems contribute to keeping ecosystems productive are valuable to natural systems but not to human-created systems are not necessary to sustainable systems

Amanager of a store that sells and installs spas wants to prepare a forecast for january and june of next year. her forecasts are a combination of trend and seasonality. she uses the following equation to estimate the trend component of monthly demand: ft = 30+5t, where t = 1 in january of this year. seasonal relatives are 0.60 for january and 1.50 for june. what demands should she predict for january and june of next year