The question asks about the importance of marine upwelling zones in increasing marine productivity. We need to identify which factors are brought to the surface by upwelling that contribute to this increase.
B) 2 only — Marine upwelling zones are important because they bring nutrient-rich waters from the deep ocean to the surface, which fuels primary production and thus increases overall marine productivity.
The question asks for the specific term describing fish deaths due to oxygen depletion under ice during winter. We need to identify the ecological term that precisely defines this phenomenon.
Correct Option: C) Winterkill is the precise term for fish deaths caused by oxygen depletion under ice during winter.
The question asks to identify the type of lake that is nutrient-rich and typically shallower. This relates to the classification of lakes based on their trophic state, which describes their productivity and nutrient levels.
Correct Option: C) Eutrophic
Eutrophic lakes are characterized by high levels of nutrients, particularly nitrates and phosphates. This abundance of nutrients supports a high rate of primary production, often leading to dense growths of algae and aquatic plants. These lakes tend to be shallower and warmer, which further contributes to higher biological activity and faster decomposition of organic matter, often resulting in oxygen depletion in deeper waters.
UPSC - 2021
The question asks about the purpose of the 'R2 Code of Practices'. This requires knowledge of environmental certifications and standards related to specific industries. Identifying the context of 'R2' is key to answering this question.
A) environmentally responsible practices in electronics recycling industry
The 'R2 Code of Practices' (Responsible Recycling) is a globally recognized standard specifically for electronics recyclers. It provides a common set of practices for environmental protection, worker health and safety, data security, and the responsible management of electronics throughout the recycling process. Its primary goal is to ensure that electronic waste is handled in an environmentally sound and socially responsible manner.
The question asks for reasons, other than poaching, for the decline in the population of Ganges River Dolphins. We need to evaluate each given statement to determine if it contributes to the decline of this species.
C) 1, 3 and 4 only — Statements 1, 3, and 4 correctly identify significant anthropogenic factors contributing to the decline of Ganges River Dolphins, other than poaching. Dams and barrages fragment habitats, accidental entanglement in fishing nets causes direct mortality, and agricultural pollution degrades their environment and health.
The question asks to identify the dominant producers in wetland ecosystems. Producers are organisms that create their own food, typically through photosynthesis, forming the base of the food web. We need to evaluate each option in the context of wetland environments.
Correct Option: B) Macrophytes are large aquatic plants that are well-adapted to the saturated soil conditions of wetlands. They include emergent plants (like cattails and reeds), submerged plants, and floating-leaved plants (like water lilies). Due to their significant biomass and widespread presence, macrophytes are the dominant primary producers in most wetland ecosystems, forming the base of the food web and providing habitat for numerous other organisms.