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

• Humidity is the measure of the amount of moisture (water vapour) in the air.
• A hygrometer is used to measure relative humidity.
• A psychrometer is an example of a hygrometer.
• Relative humidity tells us the ratio of water vapour present in the air compared with the maximum amount the air can hold at a given temperature.
• Humidity is commonly expressed as a percentage (%).

Last verified on 23-08-2026

Explanation

• Albuminurophobia is a fear of kidney disease.
• The term is associated with an excessive or irrational fear of developing kidney disease.
• Albuminuria refers to the presence of albumin (a protein) in urine.
• The term is related to concerns about kidney health and disease.

Last verified on 22-08-2026

Explanation

• Ophthalmology is the study and medical specialty concerned with the eyes and vision.
• It deals with the structure, function, diseases, and treatment of the eyes.
• A doctor specializing in this field is called an ophthalmologist.
• Common eye conditions include cataracts, glaucoma, and refractive errors.

Last verified on 08-08-2026

Explanation

Geologists are scientists who study a planet's solid features, like soil, rocks, and minerals.