Select the procedure that will not saturate a thin-layer chromatography (tlc) developing chamber with developing solvent vapors.

The correct answer is adding ninhydrin to developing solvent.

Ninhydrinis used to detect (color) amino-acids, since amino acids are colourless compounds. So, after development, the TLC plate is sprayed with ninhydrin reagent and dried in an oven, at 105°C for about 5 minutes. It reacts with α- amino acids that results in purple coloured spots.  

measuring light intensity

light meters can be used to measure light intensity. the meter is held at the soil surface and pointed in the direction of the maximum light intensity, and then the meter is read.

errors can be made when measuring light intensity by accidentally shading the light meter. the reliability of the results can be checked by taking many samples.

69 is the correct math for the amino acids