With reference to bio-toilets used by the Indian Railways, consider the following statements : 1. The decomposition of human waste in the bio-toilets is initiated by a fungal inoculum. 2. Ammonia and water vapour are the only end products in this decomposition which are released into the atmosphere. Which of the statements given above is/are correct?

Describes biogas systems that decompose organic matter in the absence of air using microorganisms to produce gas and a digested slurry.

A student could infer that engineered sanitation systems (like bio-toilets) commonly rely on microbial decomposition (though not necessarily fungi) and therefore check whether railway bio-toilets use anaerobic microbial inocula.

Notes that rubbish in landfills is used for generation of 'landfill gas' via decomposition and that leftover slurry is digested material used as manure.

One could extend this pattern to ask whether small-scale waste-treatment units (bio-toilets) mimic landfill/biogas processes and thus use microbial consortia — prompting investigation into the specific inoculum (bacterial vs fungal) used.

Mentions mycofiltration — use of fungal mycelia to filter toxic waste and microorganisms from water/soil.

Since fungi can be intentionally applied to treat wastes, a student could reasonably hypothesise and then check whether bio-toilet designs ever use fungal inocula (myco-based treatment) rather than or in addition to bacterial systems.

Explains decomposition in nature by decomposers/saprotrophs (insects, microbes) that break down dung and recycle nutrients.

Using the general rule that decomposition can be carried out by various saprotrophs, a student could consider that engineered toilets might employ specific decomposers (bacteria or fungi) and thus investigate which organisms bio-toilets adopt.

States that sewage contains human excreta and that decomposition of organic matter in water is carried out by microorganisms (putrescibility) using oxygen.

This highlights that sewage treatment relies on microbial activity (aerobic or anaerobic); a student can use this to narrow inquiry to whether railway bio-toilets use aerobic fungal processes or anaerobic bacterial digestion.

States that untreated wastes ferment slowly and release 'toxic biogas' including methane, showing methane is a common gaseous product of decomposition.

A student could infer bio-toilet decomposition likely emits methane (and other biogas components), so ammonia and water vapour are unlikely to be the only gases.

Lists gases released during planetary degassing and decomposition processes: water vapour, nitrogen, carbon dioxide, methane, ammonia, etc., providing an example set of gases associated with organic/thermal decomposition.

Use this list to check whether CO2, methane, and nitrogenous gases are plausible products from biological decomposition in bio-toilets.

Describes biogas produced from organic (including human) waste and notes the digested slurry has nutrient compounds (N, P, K), linking decomposition to both gaseous biogas and nitrogen-containing residues.

Combine this with knowledge of typical biogas composition to suspect gases other than ammonia and water vapour (e.g., methane, CO2) are emitted from bio-toilets.

Mentions landfill gas can be captured and used as biogas and reiterates large biogas potential, implying decomposition generates combustible gases (not just ammonia/water).

A student could extrapolate that systems designed to harvest biogas are targeting methane/CO2 mixtures, so similar decomposition in bio-toilets would produce such gases.

Explains that decomposition and excretion return sulfur to the environment and that hydrogen sulphide oxidizes to sulphur dioxide, showing sulfurous gases can arise from organic decay.

This suggests that, depending on inputs and anaerobic conditions, sulfur-containing gases (e.g., H2S) may be present among decomposition emissions, so ammonia/water vapour are not necessarily the only products.