There are other bacteria that use the ammonium in the water as a nitrogen source and take it up to make organic nitrogen and new bacteria. When they do this and hold the nitrogen inside bacterial cells, it is called

yes, because even though a theory has a  lot of evidence to support it, it is not always true

straight probes are used primarily for measuring flow as it is approaching the test area. its geometry allows the probe to be mounted so that it is in the direct line of airflow.