#environmental science

Environmental Effects - Ozone, Greenhouse and Safety

What protects the Earth from excessive ultraviolet radiation?

**Ozone absorbs UV** protecting life, depletion by CFCs, halons produces Cl· + O₃ → ClO + O₂, ClO + O → Cl· + O₂, catalytic cycle, one Cl destroys thousands of O₃, Montreal Protocol bans CFCs, UV increase harmful. The document mentions that the ozone layer absorbs most ultraviolet radiation from the sun at an altitude of 40-50 km . Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields Ozone layer, illustrating EM wave transverse nature and Maxwell's displacement current concept.

Ref: NCERT > Physics Book > Electromagnetic Waves > Environmental Effects - Ozone, Greenhouse and Safety

View Details

Environmental Effects - Ozone, Greenhouse and Safety

Why does the depletion of the ozone layer pose a significant health risk?

**Ozone absorbs UV** protecting life, depletion by CFCs, halons produces Cl· + O₃ → ClO + O₂, ClO + O → Cl· + O₂, catalytic cycle, one Cl destroys thousands of O₃, Montreal Protocol bans CFCs, UV increase harmful. The ozone layer absorbs most of the sun’s harmful UV radiation; its depletion allows more UV rays to reach the Earth, increasing risks of skin cancer and other health issues. Using c = fλ, E₀/B₀ = c, I_d = ε₀ dΦ_E/dt, and spectrum classification λ = c/f, evaluation yields It increases UV radiation exposure, illustrating EM wave transverse nature and Maxwell's displacement current con

Ref: NCERT > Physics Book > Electromagnetic Waves > Environmental Effects - Ozone, Greenhouse and Safety

View Details

BOTANY

Which of the following is an incorrect statement about climate change and biodiversity?

Climate change significantly impacts biodiversity by altering habitats, increasing extreme weather events, and affecting species interactions. This follows from NCERT principle where relation explains outcome clearly for students.

Ref: NCERT Biology Textbook for Class XI and XII (Botany section), Chapter: Biology - Botany portion covering relevant concept, Topic: Plant structure, physiology and applications.

View Details

BOTANY

Which of the following is NOT a reason for conserving biodiversity?

Monetary inflation is unrelated to biodiversity conservation, whereas utilitarian and ethical values justify conservation efforts. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.

Ref: NCERT Biology Textbook for Class XI and XII (Botany section), Chapter: Organism and Population, Ecosystem and Biodiversity, Topic: Ecological interactions and conservation.

View Details

Bioremediation

Bioaugmentation involves:

Bioaugmentation deliberately introduces selected allochthonous or enriched autochthonous microorganisms with laboratory-verified superior degradative capabilities to contaminated sites where native community density or catabolic potential insufficient to achieve remediation goals within regulatory timeframe. Pure cultures or consortia such as Alcanivorax borkumensis specialized for branched alkanes, Dehalococcoides mccartyi containing tceA, bvcA and vcrA reductive dehalogenase genes for complete detoxification of tetrachloroethene to ethene, and genetically engineered strains expressing broad-

Ref: Hosokawa et al. Journal Hazardous Materials 2009 Bioaugmentation strategies; NCERT Environmental Biotechnology bioaugmentation; EPA guide.

View Details

Bioremediation

Biostimulation refers to:

Biostimulation enhances pollutant degradation capacity of indigenous microbial communities already adapted to site conditions without introducing foreign organisms, focusing instead on relieving nutritional, redox or environmental constraints limiting rate. Petroleum hydrocarbons, chlorinated solvents and pesticides often persist not due to absence of degraders carrying alkB alkane hydroxylase, xylE catechol dioxygenase or dehH haloacid dehalogenase genes, but because electron acceptor oxygen, nitrogen as ammonium, phosphorus as phosphate, or carbon as electron donor scarce, causing C:N:P imba

Ref: Adams et al. Frontiers Microbiology 2015 Biostimulation vs Bioaugmentation; EPA Technical Guide biostimulation; PubMed comparison.

View Details

Bioremediation

Bioremediation is defined as:

Bioremediation encompasses deliberate application of biological agents including bacteria, archaea, fungi and plants to neutralize, transform, degrade or immobilize environmental pollutants, ultimately converting hazardous organics into less harmful end products such as carbon dioxide, water, chloride and inorganic salts. Indigenous genera Pseudomonas, Sphingomonas, Rhodococcus harbor catabolic plasmids TOL encoding toluene degradation, OCT for octane, NAH for naphthalene, and chromosomal genes nahAc non-heme iron dioxygenase, alkB integral membrane alkane hydroxylase, xylE catechol 2,3-dioxyg

Ref: EPA Bioremediation overview https://www.epa.gov/remedy/bioremediation; Vidali I J Green Chem 2001; NCERT Environmental Biotechnology.

View Details

Biodiversity Conservation - In situ Ex situ Hotspots

Which type of conservation effort involves preserving biodiversity outside natural habitats?

Ex situ conservation protects threatened plants and animals outside their natural habitats through zoological parks, botanical gardens, seed banks, and similar methods.