Life Sciences and Biology

During intense anaerobic exercise, muscle cells produce lactic acid as a byproduct of glycolysis when oxygen supply is insufficient. This accumulation leads to muscle fatigue, burning sensation, and reduced performance. Pyruvic acid (A) is a precursor converted to lactic acid, oxaloacetic acid (C) is part of the Krebs cycle, and uric acid (D) is a waste product from nucleic acid breakdown.

The hypothalamus is the body's thermoregulatory center, often called the 'thermostat.' It maintains core body temperature around 37°C through mechanisms like sweating, shivering, and blood flow regulation. The pineal gland (A) regulates sleep-wake cycles via melatonin, pituitary (B) is the 'master gland' for hormones, and thyroid (C) controls metabolic rate.

The iris is the colored part of the eye containing pigments (melanin) that determine eye color - brown, blue, green, etc. The amount and type of melanin in the iris create these variations. The cornea (A) is the transparent outer layer, choroid (B) is the vascular layer behind the retina, and vitreous body (D) is the jelly-like substance filling the eye.

Clove, the commonly used spice, is obtained from the flower bud.

 The colour of cow’s milk is slightly yellowish due to the presence of Carotene.

In lower termites, cellulose (the main component of wood) is digested by protozoans living in their hindgut. These protozoans produce cellulase enzymes that break down cellulose into simpler compounds that termites can absorb. Higher termites lack protozoans and rely solely on bacteria and their own enzymes. Option C (both) is incorrect because the question specifically asks about termites in general, where protozoans are the distinctive answer.

A parasite lives on or in a host and benefits at the host's expense. Louse, mosquitoes, and ticks are parasites. A housefly is a scavenger or vector, not a biological parasite.

Carl Linnaeus is known as the father of modern taxonomy and is responsible for the binomial nomenclature system.

Penicillin is an antibiotic derived from the Penicillium fungus.

In eukaryotic plant cells, DNA is found in the nucleus, mitochondria, and chloroplasts.

Antibodies, insulin, and pepsin are proteins. NAD+ (Nicotinamide adenine dinucleotide) is a coenzyme, not a protein.

All birds possess a cloaca, which is the common opening for the digestive, reproductive, and urinary tracts. Therefore, none of the listed birds lack one.

The hair root is the part of the hair located below the skin surface, where cell division occurs, making it the living and growing part.

Grape sugar is glucose, which is a monosaccharide. Monosaccharides do not require hydrolysis by enzymes before absorption, unlike disaccharides like sucrose or maltose.

The primary (milk) dentition in children consists of incisors, canines, and molars. Premolars are only present in the permanent adult dentition.

The dark reaction (Calvin cycle) of photosynthesis uses ATP and NADPH to fix carbon dioxide into sugar (glucose).

Insects utilize a tracheal system, a network of tubes that delivers oxygen directly to their tissues. This bypasses the need for a circulatory system to transport respiratory gases.

The fermentation process carried out by yeast releases carbon dioxide gas. This gas gets trapped in the dough, causing it to rise and increase in volume.

An artificial kidney, or hemodialysis machine, uses the principle of dialysis to remove waste products and excess fluids from the blood when the natural kidneys fail.

The conjunctiva is the thin, transparent mucous membrane that covers the inner surface of the eyelids and the white part of the eyeball. Inflammation of this membrane is known as conjunctivitis, which makes the eye appear pink.

Iodine is essential for the production of thyroid hormones. A deficiency leads to the thyroid gland enlarging as it attempts to compensate for the lack of iodine, a condition known as a goiter.

Birds and lizards are uricotelic, meaning they excrete nitrogenous waste primarily in the form of uric acid. This is a water-conserving adaptation, as uric acid is relatively insoluble and excreted as a white paste.