Tar

A thick dark-colored semi-liquid of organic composition obtained by the destructive distillation of organic substances and bituminous minerals, including wood, coal or peat.

Thallus

A plant body without true stems, leaves, and roots; characteristic of thallophytes, a class of plants that includes algae, fungi, and lichens.

Toxicology

Toxicology is the study of the adverse effects of chemical and physical agents on living organisms.

Tuber(s)

A short, solid, underground stem or root whose primary purposes are food storage and reproduction.