D.

Trichoderma

Trichoderma is a genus of fungi that is present in all soils, where they are the most prevalent culturable fungi. Many species in the genus can be characterised as opportunistic avirulent plant symbionts. Several strains of Trichoderma have been developed as biocontrol agents against the fungal disease of plants. The various mechanisms include antibiosis, parasitism inducing host-plant resistance and competition. Most biocontrol agents are from the species. T.harzianum, T. varied and T. hamatum. The biocontrol agent generally grows in its natural habitat on the root surface and so affects root disease in particular but can also be effective against the foliar disease.

A.

Aspergillus

A good producer of citric acid is Aspergillus niger (a fungus). Clostridium produces butyric acid, Saccharomyces cerevisiae is used for bread baking fermenting malted cereals and fruit juices to produce ethanol. Pseudomonas (a bacterium) is used in Vitamin -B-12 production.

B.

Anabaena

B.

streptokinase

B.

preformed antibodies

In passive immunity, the antibodies are produced in some other organism (eg, horse) in response to the given antigen,.These antibodies are then injected into the human body at the time of need. This is known as inoculation, eg, persons infected by tetanus, rabies, Salmonella and snake venom are given the sufficient amount of antibodies, so that they can survive.