Carboxyl groups have an electronegative oxygen atom double bonded to a carbon atom. This carbon-oxygen bond is very polar and the fact that its a double bond increases the polarity of the bond.
PEA agar, also referred to as Phenylethyl Alcohol Agar is a medium  used by microbiologists to grow microorganisms. The ingredient that  supplies nitrogen is casein. Making the world better, one answer at a time.
A complete fertilizer contains the three major fertilizer elements--nitrogen, phosphorus (phosphate), and potassium (potash). Fertilizer grade. The fertilizer grade designates the percentages of nitrogen, phosphate, and potash in the product.rass plants normally need nitrogen, phosphorus, and potassium (potash) in larger amounts than can be supplied naturally from the soil. Nitrogen, which is essential for vegetative growth and good green color, is a constituent of plant proteins, chlorophyll, amino acids, and other plant substances.