Azolla is a freshwater fern harboring a bluegreen alga - Anabaena in its leaf cavities. The alga fixes atmospheric nitrogen and releases nitrogenous compounds in leaf cavities. This symbiotic system is the main source of algal biofertilizer in rice fields. When rice paddies are flooded in the spring, they can be inoculated with Azolla, which then quickly multiplies to cover the water, suppressing weeds. As the plants die, they contribute nitrogen to the rice plants, and as the rice paddy dries out, the Azolla eventually die, making an exceptional green manure.

Correct Option: A

Azolla is a freshwater fern harboring a bluegreen alga - Anabaena in its leaf cavities. The alga fixes atmospheric nitrogen and releases nitrogenous compounds in leaf cavities. This symbiotic system is the main source of algal biofertilizer in rice fields. When rice paddies are flooded in the spring, they can be inoculated with Azolla, which then quickly multiplies to cover the water, suppressing weeds. As the plants die, they contribute nitrogen to the rice plants, and as the rice paddy dries out, the Azolla eventually die, making an exceptional green manure.

Azolla is a freshwater fern harbouring a bluegreen alga - Anabaena in its leaf cavities. The alga fixes atmospheric nitrogen and releases nitrogenous compounds in leaf cavities. This symbiotic system is the main source of algal biofertilizer in rice fields.

Correct Option: A

Azolla is a freshwater fern harbouring a bluegreen alga - Anabaena in its leaf cavities. The alga fixes atmospheric nitrogen and releases nitrogenous compounds in leaf cavities. This symbiotic system is the main source of algal biofertilizer in rice fields.

Azolla and blue green algae- Anabaena form biofertilizer in rice fields.

Correct Option: A

Azolla and blue green algae- Anabaena form biofertilizer in rice fields.

Butyric acid bacteria, Clostridium butylicum causes the retting of fibres. Retting is a stage in the manufacturing of vegetable fibers, especially the bast fibers. It is the process of submerging plant stems such as flax, jute, hemp or kenaf in water, and soaking them for a period of time to loosen the fibers from the other components of the stem. Retting can also be done by letting the cut crop stand in the fields in the wet fall, called “dew retting”. Bacterial action attacks pectin and lignin, freeing the cellulose fibres. The stems are then removed and washed and subjected to mechanical processing to remove the soft tissue and then dried so that all that remains are the fibres.The process is caused by Clostridium butylicum.

Correct Option: B

Butyric acid bacteria, Clostridium butylicum causes the retting of fibres. Retting is a stage in the manufacturing of vegetable fibers, especially the bast fibers. It is the process of submerging plant stems such as flax, jute, hemp or kenaf in water, and soaking them for a period of time to loosen the fibers from the other components of the stem. Retting can also be done by letting the cut crop stand in the fields in the wet fall, called “dew retting”. Bacterial action attacks pectin and lignin, freeing the cellulose fibres. The stems are then removed and washed and subjected to mechanical processing to remove the soft tissue and then dried so that all that remains are the fibres.The process is caused by Clostridium butylicum.

Downy mildew of grapes disesase is linked to the discovery of Bordeux mixture as a popular fungicide. Bordeux mixture was discovered by Millardet in France in 1882. Bordeux mixture is prepared by dissolving 40g of copper sulphate and 40 g of calcium hydroxide in 5 litres of water. Bordeux mixture is used primarily as a fungicide, it was first used to control downy mildew disease of grape-vine caused by a fungus, Plasmopara viticola. The first pesticide to be used commercially was bordeux mixture.

Correct Option: B

Downy mildew of grapes disesase is linked to the discovery of Bordeux mixture as a popular fungicide. Bordeux mixture was discovered by Millardet in France in 1882. Bordeux mixture is prepared by dissolving 40g of copper sulphate and 40 g of calcium hydroxide in 5 litres of water. Bordeux mixture is used primarily as a fungicide, it was first used to control downy mildew disease of grape-vine caused by a fungus, Plasmopara viticola. The first pesticide to be used commercially was bordeux mixture.