Explain why the nile floodplain and its annual did cycle provided an ideal situation for building an agricultural civilization

The Nile's flood plain allowed the Nile too flood certain areas for a certain amount of time. When the Nile's water receded, it left behind nutrient rich soil (silt) that was ideal for growing crops. Wherever crop can grow, that's where civilization can thrive.

 Proteins are large, complex molecules that play many critical roles in the body. They do most of the work in cells and are required for the structure, function, and regulation of the body's tissues and organs.

Explanation:

What Is Main Purpose of Protein in Living Things?

Muscle Mass. The building blocks of proteins are amino acids.

Cell Formation. Every cell in your body has some protein in it.

Tissue Maintenance and Repair. You need protein to help your body repair cells and create new ones.

Enzymes and Hormones.

Energy Source.