Why do ecosystems need a constant input of energy from an external source

Which ideas did your answer contain? check all that apply. no food for organisms no oxygen in the atmosphere no trees or flowering plants no products based on trees or plants (building materials, medicines, fuels, fibers) no fossil fuels

Which is not a likely outcome after extensive irrigation of dry farmland? useless, unproductive soil salinization of the soil depletion of groundwater nutrient-rich soil

The activity of the modern sample is 1.10 bq . how long does that measurement take?