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

Explanation

Methane (CH₄) is a potent greenhouse gas with a global warming potential over 25 times greater than carbon dioxide (CO₂) over a 100-year period. The primary sources of methane emissions can be categorized into natural and anthropogenic (human-caused) sources.

Option 1 is correct: Rice fields emit methane due to the anaerobic decomposition of organic matter in waterlogged conditions. This is a significant contributor to global methane emissions, particularly in rice-producing countries.

Option 2 is correct: Coal mining releases methane trapped within coal seams during the mining process. This is known as fugitive methane emissions and is a key source of industrial methane.

Option 3 is correct: Domestic animals, particularly ruminants like cattle and sheep, produce methane during enteric fermentation, a digestive process where microbes break down food in the stomach.

Option 4 is correct: Wetlands are natural sources of methane, produced through the anaerobic decomposition of organic material in water-saturated soils.

Explanation

Option (a) is incorrect: Passion flower plant is not an insectivorous plant. Passion flowers are flowering plants, typically known for their beautiful blooms and use in ornamental gardening.

Option (b) is correct: Pitcher plant is an insectivorous plant that derives nutrients by trapping and digesting insects. Its leaves are modified into pitcher-like structures containing digestive fluids. Insects are lured by the plant’s bright colors and nectar and are trapped when they fall into the pitcher. This adaptation helps the plant survive in nutrient-poor soils such as those lacking nitrogen.

Option (c) is incorrect: Night queen also known as Raat ki Rani, this is a type of flowering plant known for its fragrant flowers that bloom at night. It is not insectivorous.

Option (d) is incorrect: Flame of the forest is a flowering tree (also known as Butea monosperma), primarily used for its ornamental and medicinal properties, and is not an insectivorous plant.

Explanation

Probiotic foods are those that contain live microorganisms, typically bacteria or yeast, which confer health benefits to the host (usually humans) when consumed in adequate amounts. Common examples include sauerkraut, miso, tempeh, pickles, lassi, kombucha, and natto.

Statement 1 is correct: Probiotic food contains live beneficial bacteria, such as Lactobacillus and Bifidobacterium, which promote gut health. These bacteria are often present in fermented foods like yogurt, kimchi, and kefir.

Statement 2 is correct: Probiotic food plays a key role in maintaining a healthy gut flora by balancing the microorganisms in the digestive system. This is crucial for digestion, immune function, and preventing gastrointestinal disorders such as diarrhea and irritable bowel syndrome (IBS).