Biotechnology may be defined with a general or a specific reference, although the latter tends to be preferred in scientific literature. This specific or specialized meaning refers to the use of living materials as tools not only to manipulate the forms or functions of other living materials, as in recombinant DNA techniques, but also as agents for control of water pollution, reduction of frost damage to crops, and the recovery of metallic ores. The definitive condition of this special meaning is the instrumental use of living material. 1