Which of these is a large reservoir of nitrogen that is unusable by most organisms? soil
atmosphere
ocean
outer space

Which properties describe all matter?

Aeukaryotic cell must be from a plant if the cell a) a nucleus b) a nuclear envelope c) cytoplasm d) a cell wall

Which of the following statements is true? 1. the mantle of the earth is made of solid nickel and iron. 2. the crust of the earth is made of solid nickel and iron. 3. the inner core is made of solid nickel and iron.