How does leaving a piece of land fallow improve the health of the soil ?

Calculate the mass of silver needed to react with chlorine to produce 126g if silver chloride?

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.

When did stem cell research become known ? who discovered stem cell? what experiments or studies have been conducted so far?