Biology: Botany: UPSC Previous Year Questions (Science and Technology)

Explanation

Statement 1 is correct: Spirogyra and Ulothrix are types of blue green algae that can be found in both freshwater and marine environments. They are typically found in ponds, rivers, and even oceans in some cases. Spirogyra is known for its spiral-shaped chloroplasts and forms slimy green filaments/ mats on the water surface, especially when nutrients like nitrogen and phosphorus are abundant while Ulothrix is characterized by its simple, unbranched filaments and typically grows in both freshwater ponds and coastal regions. These algae play an important role in the aquatic food chain.

Statement 2 is correct: Chameleons have a unique ability to move their eyes independently of each other. They can focus one eye on an object in front while the other eye looks in a different direction, even behind them. This independent eye movement enables them to have a 360-degree view of their surroundings, aiding in predator detection and prey surveillance.

Explanation

Saturated fats are typically solid at room temperature and are found in animal products like butter, lard, and fatty cuts of meat, as well as some plant oils like coconut and palm oil. They are composed of fatty acids with no double bonds between carbon atoms, making them less reactive. Unsaturated fats are liquid at room temperature and are mainly found in plant-based oils (such as olive, sunflower, and canola oil) and fish. They contain one or more double bonds between carbon atoms which introduce "kinks" in the structure making them more reactive and beneficial for heart health when consumed in moderation. Assertion (A) is true: Unsaturated fats have at least one double bond between carbon atoms, making them more reactive. These double bonds are sites where chemical reactions can occur more easily compared to the single bonds in saturated fats. Reason (R) is false: Unsaturated fats contain at least one double bond in their carbon chain, not only single bonds. Saturated fats have only single bonds.

Explanation

Statement 1 is correct: Molasses is a thick, dark syrup that remains after the extraction of sugar from sugarcane or sugar beets. It is a common by-product in the sugar industry. It serves as a feedstock for producing synthetic chemical fertilizers and ethanol.

Statement 2 is correct: Bagasse, the fibrous residue left after extracting juice from sugarcane, is commonly used as a biofuel in the sugar industry to generate steam and electricity, making the process more energy-efficient.

Statement 3 is incorrect: Sugar is produced from various raw materials including sugarcane and sugar beets. Other sources for sugar production include sorghum and palm sap.