CGPSC MAINS 2019 Paper-4

Points to Remember: Main soil pollutants: heavy metals, pesticides, herbicides, fertilizers, plastics, pathogens. Sources of pollution: industrial discharge, agricultural practices, improper waste disposal. Impacts: human health risks, ecosystem disruption, reduced agricultural productivity. Remediation techniques: phytoremediation, bioremediation, chemical remediation. Introduction: Soil pollution, the contamination of soil with harmful chemicals or substances, is a significant environmental problem … Read more

Points to Remember: The man earns ₹200 and spends ₹150 in a two-day cycle. Net earnings per cycle are ₹50 (₹200 – ₹150). We need to determine the day when his total savings reach ₹600. Introduction: This is a mathematical word problem requiring an analytical approach. It involves calculating cumulative savings based on a repeating … Read more

Points to Remember: Nuclear fusion Proton-proton chain reaction Hydrogen to Helium conversion Energy release Gravitational pressure Introduction: The Sun, the star at the center of our solar system, is a colossal sphere of incandescent plasma. Its immense energy output, responsible for life on Earth and the dynamics of our solar system, originates from a process … Read more

Points to Remember: Aerobic respiration is the process by which plants break down glucose in the presence of oxygen to release energy. It occurs in the mitochondria and involves several key stages: glycolysis, the Krebs cycle, and the electron transport chain. The energy released is stored in ATP molecules, which are used to power various … Read more

Points to Remember: Transportation of gases, nutrients, hormones, and waste products. Regulation of body temperature, pH, and fluid balance. Protection against infection and blood loss. Introduction: Blood, a vital connective tissue, is a complex fluid circulating throughout the body. It constitutes approximately 7-8% of an adult’s total body weight, with an average volume of 5 … Read more

Points to Remember: Median is the middle value in an ordered dataset. For grouped data (frequency distribution), the median needs to be calculated using the cumulative frequency. The formula for calculating the median for grouped data involves identifying the median class and applying a specific formula. Introduction: The question requires calculating the median for a … Read more

Points to Remember: Definition and causes of acid rain. Effects of acid rain on the environment and human health. Sources of acid rain pollutants. Mitigation and prevention strategies. International and national efforts to control acid rain. Introduction: Acid rain, a term encompassing any form of precipitation with acidic components, such as sulfuric or nitric acid … Read more

Points to Remember: Definition and principles of bioremediation. Types of bioremediation techniques (in-situ and ex-situ). Advantages and disadvantages of bioremediation. Applications of bioremediation in environmental cleanup. Limitations and future prospects of bioremediation. Introduction: Bioremediation is a sustainable and environmentally friendly technology that utilizes biological organisms, primarily microorganisms like bacteria and fungi, to degrade or remove … Read more

Points to Remember: Definition and characteristics of non-degradable pollutants. Examples of non-degradable pollutants. Environmental and health impacts. Mitigation and management strategies. Introduction: Pollution, the contamination of the environment with harmful substances, poses a significant threat to ecological balance and human health. Pollutants are broadly classified as degradable and non-degradable based on their ability to decompose … Read more

Points to Remember: Definition and properties of alkali metals. High reactivity of alkali metals. Reasons for their non-occurrence in free state. Examples of alkali metals and their reactions. Introduction: Alkali metals are a group of chemical elements that belong to Group 1 of the periodic table. They are characterized by their highly reactive nature and … Read more