Saccharides are an important source of energy for our bodies.

The bottom sediment of this lake is mainly composed of sand and mud.

He has a susceptibility to depression, and tends to get down over little things.

He has cyclothymia, and his mood changes drastically.

Protein is a nutrient necessary for muscle growth.

His teeth have strong dentin, making them less prone to cavities.

Dentin is a major part of the tooth, located under the enamel.

That dog is reputed to be vicious.

The properties of electrolytes are one of the important themes in physical chemistry.

The cytoplasm contains various substances necessary for cellular activity.