(a) Controlling the viral diseases spread by mosquitoes

(b) Converting crop residues into packing material

(c) Producing biodegradable plastics

(d) Producing biochar from thermo-chemical conversion of biomass

Ans: a

Explanation:

How mosquitoes spread diseases?

• Mosquitoes do not naturally carry viruses – they can only get them from infected people. 
• Since only female mosquitoes bite humans, only female mosquitoes can transmit viruses.
• Mosquitoes pick up viruses by biting infected people. When they bite again, they can transmit the virus to the next person. This is how mosquito-borne diseases spread.
• The Aedes aegypti mosquito is the main transmitter of dengue, Zika, chikungunya and yellow fever viruses. 
• Aedes aegypti mosquitoes originated in Africa, but they have spread through tropical and subtropical regions around the world.

About Wolbachia 

• Wolbachia is one of the world’s most common types of bacteria, present in 50% of all insect species, including bees, beetles, butterflies, moths, and fruit flies. . Wolbachia bacteria cannot make people or animals (for example, fish, birds, pets) sick.
• Wolbachia lives inside insect cells and is passed from one generation to the next through an insect’s eggs. Aedes aegypti mosquitoes don’t normally carry Wolbachia, however many other mosquitoes do.
• Wolbachia blocks viruses like dengue, chikungunya and Zika from growing in the bodies of Aedes aegypti mosquitoes.  This means that Wolbachia mosquitoes have a reduced ability to transmit viruses to people.  
• When Wolbachia is established in a mosquito population it results in a decreasing incidence of dengue, Zika, chikungunya.
• World Mosquito Program, breeds Wolbachia mosquitoes. Then, in partnership with local communities, release them into areas affected by mosquito-borne diseases.
• Which means less risk of disease in communities where Wolbachia is established in the local mosquito population.
• Wolbachia method can protect communities from mosquito-borne diseases without posing risk to natural ecosystems. This method is natural and self-sustaining. 
• People are constantly exposed to Wolbachia through the foods they eat and the insects that bite them, but it causes no known health risks. It also does not affect the food chains of other species because Wolbachia does not reduce mosquito populations.
• Other methods of controlling mosquitoes are Insecticide spraying, the Sterile Insect Technique, the Incompatible Insect technique, and Genetic Modification. But these techniques are not self-sustaining.

Hence, option a is correct.

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