(a) Collecting DNA samples from air in a habitat at one go

(b) Understanding the genetic makeup of avian species of a habitat

(c) Using air-borne devices to collect blood samples from moving animals

(d) Sending drones to inaccessible areas to collect plant and animal samples from land surfaces and water bodies

2. Ans: a

Explanation:

Metagenomics: 

Meta derives from the Greekword, which encompasses a wide array of meanings, such as “with”, “after”, “alongside”, “on top of” and “beyond”.

Metagenomics, , is the study of the total genetic material directly obtained from the microorganisms living in a particular environment, like microbes living in the animal gut or in any particular ecological environment. Metagenomics projects are used to study the genomics of community of organisms. 

Applications  of Metagenomics  

• It helps to study the diversity of microbial communities and how the diversity of these microbes changes with changes in the environment.
• Metagenomics may also help in identifying novel genes or enzymes with the significant industrial applications. For example, the study of microbial communities living in extreme environments, like high temperature sulphur springs can help to identify the novel enzymes that are resistant and functional at such high temperatures. Thus, metagenomics has applications in understanding  the genomes of gut microbes, throat microbes, microbes present on a toilet seat, and many more. 
• It provides an insight about the genome of diverse forms of microbes and their correlations. For example, study of genomes of diverse forms of viruses may provide an understanding about virus-host interaction, epidemiology and also evolution of viruses. 

Environmental DNA (eDNA)  and Aerial Metagenomics 

DNA can be easily released by an organism , all living beings constantly shed bits of DNA, left behind from skin, scales, hair, urine, feces, pollen and more  into environment, such a DNA is called Environmental DNA (eDNA). This DNA can be found in air, water, or soil. 

All species shed DNA during life or in death, providing an opportunity to monitor biodiversity via environmental DNA (eDNA).

This environmental DNA, or eDNA, has “changed everything” about how scientists study biodiversity and conservation.

Aerial Metagenomics is about extracting eDNA from the atmosphere. It involves plucking the DNA concerned from thin air.

Hence, option a is correct.

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