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.
In addition to heat, peas need moisture to germinate. While dormant, pea seeds store food in their endosperms, or inner tissues, and in their cotyledons, or first leaves. As they absorb water, this food is released and converted into energy needed by the developing embryo.