Why are bacteria such as Rhizobium and cyanobacteria so important in the nitrogen cycle?
A. They return nitrogen gas to air
B. They fix atmospheric nitrogen gas for the food chain
C. They decompose dead plants and animals
D. They build protein in plants

18. determine whether each stateme blank space given. ach statement is true (t) or false (f). place your answer in the 8. when a cell is put into an isotonic solution, individual wat put into an isotonic solution, individual water molecules cannot move back and forth across the cell membrane. d. when a cell is put into a hypertonic solution, there is a net movement of water molecules across the cell membrane into the cell. c. when a cell is put into a hypotonic solution, there is a net movement of water molecules across the cell membrane out of the cell. d. the movement of any solvent across a semi-permeable membrane is called osmosis. e. carrier proteins have the ability to change shape and physically move molecules across the cell membrane. f. in facilitated diffusion, the concentration of the molecules to be moved across the cell membrane is higher inside the cell.

Apond, rich in various micro-organisms, dries up due to drought. how will the amoeba in the pond protect themselves from this unfavorable condition?

The actual boiling point of pure water is 100.0°c. what can be concluded from the data about the reliability and validity of the thermometers?