Everyday Science

Muscle fatigue is primarily caused by the accumulation of lactic acid in the muscles during intense exercise, which leads to a burning sensation and decreased muscle performance.

Wood is primarily used as the raw material for manufacturing paper, as it contains cellulose fibers essential for paper production. Paint, gunpowder, and ink do not use wood as their main raw material.

Gypsum is commonly used to treat alkaline soils because it helps to displace sodium ions and improve soil structure, making the soil more suitable for cropping.

Afternoon rains in equatorial regions are typically caused by convectional rainfall, which occurs when the sun heats the land surface, causing warm air to rise, cool, condense, and form rain clouds in the afternoon.

Hydrogen gas is commonly used in the manufacture of banaspati ghee through the process of hydrogenation, which converts liquid vegetable oils into semi-solid fats.

Freon and ammonia are commonly used refrigerants in domestic refrigerators due to their suitable thermodynamic properties. Neon, spirit, and methane are not typically used as refrigerants in household refrigeration.

Most drugs are primarily excreted through the kidneys via urine, which is the main route for elimination of many substances from the body. Other routes like skin, gallbladder, and lungs play minor roles in drug excretion.

Rubber trees thrive in warm and humid climates, which provide the ideal conditions for latex production. Such climates ensure sufficient moisture and temperature for optimal growth.

Rancidity in butter occurs due to the oxidation of fats and oils. Quinoline helps slow down this oxidation process, thereby reducing rancidity. Therefore, quinoline acts as an inhibitor (antioxidant) in this reaction.

Spinach leaves are well known for being rich in iron, which is essential for blood production and oxygen transport in the body. While spinach contains other nutrients, iron is the most notable and relevant answer here.