When water is added to saline-alkaline soil, the dilution effect reduces the concentration of dissolved salts, leading to a decrease in electrical conductivity (Ec). Simultaneously, the hydrolysis of sodium carbonate and other alkaline salts often leads to an increase in the pH of the soil solution, making it more alkaline.

The C/N ratio indicates the relative proportion of carbon to nitrogen in organic matter. Groundnut cake, a byproduct of oil extraction, is highly concentrated in nitrogen compared to bulkier organic materials like compost or farmyard manure (FYM). Because of its high nitrogen content, it possesses a significantly lower C/N ratio, making it an excellent source of readily available nitrogen for plant growth compared to materials with higher carbon content.

Thermophilic bacteria are microorganisms that thrive at relatively high temperatures, typically between 45°C and 80°C, with an optimum often near 55°C. These organisms possess heat-stable enzymes and specialized cell membranes that allow them to function efficiently in environments that would denature the proteins of other bacteria. They are commonly found in hot springs, compost piles, and industrial fermentation processes where high temperatures are maintained.

Muscovite is the most common and prominent member of the mica group of minerals. It is a hydrated phyllosilicate mineral composed of aluminum and potassium, often referred to as potash mica or isinglass. Muscovite is widely distributed in various geological environments, including granites, pegmatites, gneisses, and schists. Its characteristic perfect basal cleavage allows it to split into thin, flexible, and transparent sheets, making it a significant mineral in both geological and industrial contexts.

Jim Corbett National Park, located in the Nainital district of Uttarakhand, is India's oldest national park. It was established in 1936 during the British colonial period, originally named Hailey National Park. The park is renowned for its diverse landscape, which includes hills, riverine belts, marshy depressions, and grasslands, providing a critical habitat for a wide variety of wildlife, including the Bengal tiger, and serving as a cornerstone for wildlife conservation efforts in India.

Grey spot disease in oats is a physiological disorder caused by a deficiency of Manganese (Mn). Symptoms typically manifest on younger leaves as chlorotic spots that eventually turn grey-white or brown and coalesce. This deficiency often occurs in soils with high pH or organic matter content, which can limit the availability of manganese to the plant roots, leading to stunted growth and reduced yields.

A sill is a tabular sheet of igneous rock that has intruded between and parallel to older layers of sedimentary rock or beds of volcanic lava. They form when magma forces its way into horizontal cracks or weaknesses in the crust. While dikes also form in cracks, they are typically discordant, meaning they cut across existing rock layers, whereas sills are concordant.

The provided answer (100,000°C) is factually incorrect according to standard solar physics, which estimates the photosphere's temperature at approximately 5,500°C to 6,000°C. The option 6000°C is the scientifically accepted value. This discrepancy may arise from a misunderstanding of solar layers or a typographical error in the source material.

Metamorphic rocks are formed through the transformation of pre-existing igneous, sedimentary, or other metamorphic rocks. This process, known as metamorphism, occurs when rocks are subjected to intense heat and high pressure deep within the Earth's crust. These conditions cause physical and chemical changes, such as recrystallization and the development of new mineral assemblages, without the rock melting into magma.

Recovery efficiency is a metric used to evaluate how effectively a crop utilizes applied fertilizers. It is defined as the difference in total nutrient uptake in the above-ground biomass between a fertilized crop and an unfertilized control crop, expressed as a percentage of the total amount of nutrient applied. This calculation allows agronomists to determine the efficiency of nutrient absorption by the plant.