Which statement best describes an effect of the low density of frozen water in a lake? a. when water freezes, it contracts, decreasing the water level in a lake. b. water in a lake freezes from the bottom up, killing most aquatic organisms. c. when water in a lake freezes, it floats, providing insulation for organisms below. d. water moves thermal energy from the land around a lake, causing the lake to freeze.

step 1: nitrogen fixation- conversion of atmospheric no₂ into forms useful to plants by lightning, bacteria, and cyanobacteria.

step 2: nitrification-process of converting ammonia to nitrite or nitrate.

step 3: assimilation-plant roots absorb new form of nitrogen.

step 4: ammonification-conversion of organic nitrogen to ammonia by bacteria involved in decomposition.

step 5: denitrification-bacteria turns the decomposed matter back into n₂o, which is released into atmosphere; repeat cycle.

your spelling is a little off : ]