What is percipatation

Chen drew a diagram to compare the ways in which different organisms obtain nitrogen. which label belongs to the area marked z?

Sodium nitrite (nano2) reacted with 2−iodooctane to give a mixture of two constitutionally isomeric compounds of molecular formula c8h17no2 in a combined yield of 88%. draw reasonable structures for these two isomers. click the "draw structure" button to launch the drawing utility. place the two compounds in the appropriate boxes below.

Why do lunar and solar eclipse not happen every month