Explanation

• O⁻ (O Negative) is the universal donor blood group.
• It can be transfused to A, B, AB, and O blood groups.
• O⁻ blood lacks A, B, and Rh (D) antigens.

Additional information:

• Universal Recipient: AB⁺ (AB Positive)
• ABO Blood Groups: A, B, AB, O
• Rh Types: Positive (+) and Negative (−)
• Total Common Blood Groups: 8 (A⁺, A⁻, B⁺, B⁻, AB⁺, AB⁻, O⁺, O⁻)

Last verified on 14-07-2026

Explanation

• The reciprocal of bulk modulus is called compressibility.
• Formula: Compressibility = 1 / Bulk Modulus
• Bulk modulus measures resistance to compression.
• Symbol: β = 1/K.
• SI unit: Pa⁻¹ (per Pascal).
• Higher bulk modulus means lower compressibility

Last updated 18-07-2026 by NA

Explanation

• Bones do not secrete hormones,
• Hormones are produced by glands in the endocrine system.
• The parathyroid gland secretes parathyroid hormone.
• It regulates calcium levels in the blood and bones.

Addition information 

• Functions performed by bones in the human body:
• Support: Provides a rigid framework for soft tissues.
• Protection: Shields vital organs like the brain, heart, and lungs.

Last updated 18-07-2026 by NA

Explanation

• The instrument used to measure temperature is called a thermometer.
• A thermometer shows how hot or cold an object or place is.

Additional information:

• Barometer measures air pressure.
• Hygrometer measures humidity (moisture in air).

Last verified on 16-06-2026

Explanation

• The SI unit of electric current is Ampere (A).
• Electric current measures the flow of electric charge.
• Defined using the elementary charge (e = 1.602176634 × 10⁻¹⁹ C).
• Named after: André-Marie Ampère (scientist).
• 1 Ampere = 1 Coulomb per second (1 A = 1 C/s).

Last verified on 08-06-2026

Explanation

• Kilometers per second: ≈ 300,000 km/s
• Speed in vacuum: 299,792,458 m/s
• Approximate value: 3 × 10⁸ m/s
• Symbol: c
• Distance traveled in 1 second: About 300,000 km
• Light from the Sun takes about 8 minutes 20 seconds to reach the Earth.

Last verified on 16-05-2026

Explanation

• The lungs are located in the thoracic cavity.
• The thoracic cavity is the chest cavity protected by the rib cage.
• It contains the lungs, heart, trachea, and major blood vessels.
• The lungs are enclosed by the pleural membranes.
• This cavity plays a vital role in breathing and respiration.

Last verified on 18-07-2026

Explanation

• White goods are durable consumer goods, mainly large household electrical appliances.
• The term originally referred to appliances that were usually finished in white enamel.
• These products are designed for long-term household use.
• Examples: Refrigerator, Washing Machine, Air Conditioner, Dishwasher, Deep Freezer

Additional information:

• Brown goods include entertainment electronics such as TVs, radios, and audio systems.

Last verified on 18-07-2026

Explanation

• The speed of sound is maximum in solids 
• Because particles are tightly packed, allowing faster vibration transfer.
• In iron, sound travels around 5120 m/s,
• Much faster than in air (343 m/s) or water (1482 m/s).

Last updated 17 july 2026 by NA

Explanation

• Surface tension prevents water from penetrating waterproof materials.

Additional information 

• Friction: Force that opposes the motion between two surfaces in contact.
• Adhesion: Attraction between molecules of different substances.
• Gravity: Force that pulls objects toward the Earth

Last updated by NA on 16-07-2026