What is the term used to describe the solid rock that lies beneath the soil? a. sand b. bedrock c. clay d. loam

How can primary sewage treatment be used as a source of biofuel? a.Fermentation of BOD allows ethanol to be produced b.After primary treatment, the water is clean enough to use for hydrogen fuel c.Lipids that collect on the surface can be collected for biodiesel d.The trickling filters captures sludge that can be used for hydrogen fuel

Which example below is a positive feedback relevant to Earth’s global energy balance? a. Increased temperature causes snow to melt. This exposes bare ground, which absorbs more solar radiation than snow, leading to further increases in temperature. b. Increased temperature causes snow to melt, which allows increased vegetation to remove CO2 from the atmosphere thereby reducing temperature. c. Increased temperature causes more solar radiation to enter the atmosphere thereby further increasing temperature. d. Increased CO2 causes the oceans to become more acidic which causes oceanic volcanoes to erupt releasing more CO2 into the environment. e. Burning fossil fuels releases CO2, which traps long-wave radiation causing temperatures to increase.

A soil consists of layers called ________ that taken together are called a ________. a. soil profiles : horizon b. horizons : soil profile c. horizons : humus d. humus : soil profile