The atmosphere is full of nitrogen gas (N2). But plants cannot use nitrogen in this form. Summarize the roles of bacteria in making nitrogen available to plants and in returning nitrogen to the atmosphere.

Prokaryotes play several roles in the nitrogen cycle. Nitrogen-fixing bacteria in the soil and within the root nodules of some plants convert nitrogen gas in the atmosphere to ammonia. Nitrifying bacteria convert ammonia to nitrites or nitrates Denitrifying bacteria converts nitrates back to nitrogen gas.

airlines i think? or a cruise boat? does this work out for u? ?

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.