Explanation: Inside a sealed pressure cooker, the pressure is higher than atmospheric pressure, which raises the boiling point of water to about 121℃. This allows food to cook faster because water and steam reach higher temperatures than at normal atmospheric pressure.

Explanation: Vitamin K is produced by gut bacteria (Escherichia coli) in the large intestine. It plays a vital role in the synthesis of prothrombin, a protein essential for normal blood clotting. Although some of it is obtained from food (like leafy vegetables), intestinal bacteria supply a significant portion of the body’s requirement.

Hepatitis is a disease that primarily affects the liver. It is characterized by inflammation of the liver tissues and can be caused by viral infections (such as Hepatitis A, B, C, D, and E viruses), excessive alcohol consumption, toxins, or autoimmune conditions. Symptoms include jaundice (yellowing of the skin and eyes), fatigue, nausea, and abdominal pain. Severe or chronic hepatitis can lead to liver failure or cirrhosis if left untreated.

Other options (for context)

• Pancreas: Affected by diseases like pancreatitis or diabetes, not hepatitis.
• Spleen: Involved in blood filtration and immunity, not affected by hepatitis.
• Small intestine: Responsible for digestion and absorption of food, not linked to hepatitis.

Explanation: Trichology is derived from the Greek word “trikhos”, meaning hair. It is a specialized field within dermatology that focuses on the structure, function, and diseases of hair and scalp. Trichologists diagnose and treat conditions such as hair loss (alopecia), dandruff, scalp infections, and hair shaft disorders.

Common Hair Disorders Studied in Trichology:

• Alopecia: Hair loss due to genetics, stress, or autoimmune disorders.
• Dandruff (Seborrheic dermatitis): Scalp condition causing flaking and itching.
• Tinea capitis: Fungal infection of the scalp (ringworm).

Explanation: In 1643, Italian scientist Evangelista Torricelli invented the barometer, an instrument used to measure atmospheric pressure. His mercury barometer demonstrated that air has weight and that atmospheric pressure can support a column of mercury in a glass tube.

Explanation: Leguminous crops such as peas, beans, gram, and clover have a symbiotic relationship with Rhizobium bacteria in their root nodules. These bacteria convert atmospheric nitrogen into ammonia, enriching soil fertility naturally. Hence, legumes are used in crop rotation to restore nitrogen content in soil.

Explanation: Hardware refers to the physical components of a computer that can be seen and touched, such as the monitor, keyboard, mouse, CPU, and printer. In contrast, software consists of programs and instructions that control the hardware and perform tasks.

Ocean Thermal Energy (OTE) is produced due to the temperature difference at different levels in the ocean. The surface water is warmer because it absorbs sunlight, while the deeper layers remain cold. This temperature gradient is used to run a heat engine that generates electricity — a process known as Ocean Thermal Energy Conversion (OTEC).

• Tides: Related to gravitational pull, not temperature.
• Pressure difference: Exists but not used for energy generation.
• Waves: Used in wave energy systems, not OTEC.

Explanation: During photosynthesis, green plants use sunlight to convert carbon dioxide (CO₂) and water (H₂O) into glucose (C₆H₁₂O₆) and oxygen (O₂). The oxygen gas released in this process comes specifically from the splitting of water molecules — a reaction known as photolysis of water, which occurs in the light-dependent reaction inside the chloroplasts.

Chemical equation:

6CO₂ + 12H₂O → C₆H₁₂O₆ + 6O₂ + 6H₂O

The oxygen atoms in the released O₂ come entirely from the original water molecules, as demonstrated by isotopic experiments using heavy oxygen (O¹⁸) tracers.