Question

Montreal Protocol refers to
(a) Substances that deplete the ozone layer
(b) Persistent organic pollutants
(c) Global warming and climate change
(d) Biosafety of genetically modified organisms

Answer 1

Hint: Montreal Protocol was signed in 1987 and finalized in 1989. It is an international treaty aimed at phasing out certain substances like the Chlorofluorocarbons (CFCs) and Hydrochlorofluorocarbons (HCFCs).

Complete answer:
Montreal Protocol is a treaty that was designed to protect the ozone layer from depletion by phasing out certain substances. It provided a treatise for the nations to phase out the use of eight recognized ozone-depleting substances and search for their alternatives. It is binding on all the countries that have ratified it and hence it has shown some remarkable success.
Chlorofluorocarbons and hydrochlorofluorocarbons are volatile halogenated hydrocarbon molecules containing carbon, hydrogen, and halogens like fluorine and chlorine, and are produced as derivatives of hydrocarbons like methane, ethane, and propane and they are also commonly known as Freons.
Traditionally many CFCs have been widely used as coolants in refrigerators and other appliances, propellants in aerosol applications, and as solvents. They deplete the ozone layer when CFCs drift into the stratosphere and are broken down by the UV radiation which releases chlorine atoms that destroy the ozone.
- Montreal Protocol is a treaty that refers to substances that deplete the ozone layer
- Stockholm convention was a treaty signed for persistent organic pollutants.
- Kyoto Protocol is the treaty signed for global warming and climate change.
- Cartagena Protocol was signed for the biosafety of genetically modified organisms.
So, the answer is, “Substances that deplete the ozone layer”.

Note:
- CFCs and HCFCs also contribute to the greenhouse effect and global warming - The greenhouse effect or Global warming is the increase in temperature of the atmosphere due to the entrapment of radiation due to gases water vapor, carbon dioxide, methane, nitrous oxide, and ozone. - Since the Montreal Protocol, many countries have ratified it and replaced the CFCs with viable alternatives.