Environmental Science MCQ – Asked in Previous Years, WBCS Mains

Answer – B. Microscopic floating organisms Plants and animals.
Explanation-
Plankton refers to the diverse community of microscopic or small organisms that drift or float in the water column of oceans, seas, and freshwater bodies. Plankton consists of both plant-like organisms called phytoplankton, which are photosynthetic and include microscopic algae, and animal-like organisms called zooplankton, which are tiny animals or the early life stages of larger aquatic animals. Plankton play a crucial role in aquatic ecosystems as they form the foundation of the food chain, provide oxygen through photosynthesis, and serve as indicators of water quality and environmental changes.

Answer – D. All of the above
Explanation-The biotic environment encompasses all living organisms and their interactions within an ecosystem. It includes producers (plants and other autotrophic organisms that produce food through photosynthesis or chemosynthesis), consumers (organisms that obtain energy by consuming other organisms or organic matter), and decomposers (organisms that break down dead organic material and recycle nutrients back into the ecosystem). The biotic environment is characterized by the interdependence and interactions between different organisms, which collectively influence the structure and functioning of ecosystems.

Answer – D. A biotic community and its non-living elements.
Explanation-
An ecosystem is a functional unit composed of a biotic community (all living organisms in a particular area) and its non-living or abiotic components. It encompasses the interactions between organisms and their physical environment, including factors such as climate, soil, water, sunlight, and nutrients. The biotic community consists of different species that interact with one another and with the abiotic components, forming complex ecological relationships and energy flow pathways. Together, the biotic and abiotic components of an ecosystem shape its structure, dynamics, and ecological processes.

Answer – A. Coprophagic
Explanation-Decomposers that specifically act on the fecal matter of other organisms are called coprophagic decomposers. “Copro-” refers to fecal matter, and “phagic” means to eat or consume. These decomposers specialize in breaking down and decomposing the organic matter present in feces. They play a vital role in the decomposition process, breaking down complex organic compounds into simpler forms and releasing essential nutrients back into the ecosystem. Coprophagic decomposers contribute to the nutrient cycling and recycling within ecosystems, facilitating the breakdown and recycling of organic matter from feces.

Answer – A. Chloro Fluoro Carbons (CFC)
Explanation-The major cause of ozone depletion is attributed to Chloro Fluoro Carbons (CFCs). CFCs are a class of synthetic chemicals that were widely used in various industrial and consumer applications, such as aerosol propellants, refrigerants, foam-blowing agents, and solvents. When released into the atmosphere, CFCs can reach the stratosphere, where they are broken down by ultraviolet radiation. These breakdown products release chlorine and bromine atoms, which act as catalysts in the destruction of ozone molecules. The chlorine and bromine atoms react with ozone, leading to the depletion of the ozone layer that protects Earth from harmful ultraviolet (UV) radiation.

Answer – B. Brazil
Explanation-

Answer – B. 2002
Explanation-The Biodiversity Act was passed in India in 2002. The act is officially known as the Biological Diversity Act, 2002, and it provides a legal framework for the conservation, sustainable use, and equitable sharing of benefits derived from biodiversity. The act aims to protect and preserve the country’s rich biodiversity, promote conservation measures, regulate access to biological resources, and ensure fair and equitable sharing of benefits arising from their utilization. It also establishes the National Biodiversity Authority (NBA) as the central regulatory body for biodiversity-related matters in the country.

Answer – B. 1905
Explanation-The Bengal Smoke Nuisance Act came into effect for the first time in 1905. The act was enacted to address the issue of air pollution caused by smoke emissions from industrial and domestic sources in Bengal, which includes present-day West Bengal and Bangladesh. The act aimed to regulate and control smoke emissions to protect public health and improve air quality. It set standards for industrial smoke emissions, prescribed penalties for non-compliance, and established mechanisms for monitoring and enforcement. The act was an early attempt to address air pollution concerns and promote environmental protection measures.

Answer – B. 1996
Explanation-The green bench in Kolkata High Court, also known as the Calcutta High Court, was established in 1996. The green bench is a specialized division within the High Court that focuses on environmental and ecological matters, including cases related to environmental pollution, conservation, and sustainable development. The establishment of green benches in various high courts across India aims to expedite environmental litigation, provide specialized expertise, and ensure effective adjudication of environmental issues. These benches play a crucial role in addressing environmental concerns and enforcing environmental laws and regulations.

Answer – C. microbes
Explanation- The activated sludge treatment process is carried out by microbes. Activated sludge is a biological treatment method used in wastewater treatment plants to break down organic matter and remove pollutants from wastewater. In this process, wastewater is mixed with a microbial culture called “activated sludge,” which contains a diverse community of microorganisms, including bacteria and protozoa. These microbes use the organic matter present in the wastewater as a food source and metabolize it, converting it into biomass, carbon dioxide, and water. The activated sludge process relies on the activity of these microorganisms to treat and purify wastewater effectively.