Why do certain epithelial cells in the nephron , but not other cells, change their water permeability in response to ADH ? Only cells that respond to ADH : A. express the gene encoding the ADH receptor
B. express the aquaporin channel gene.
C. come into direct contact with ADH.

D. carry the gene encoding the ADH receptor.

E. need to have their permeability regulated.

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.