Explanation

• The age of a tree is determined by its Rings (Number of Annual Rings).
• Each annual ring generally represents one year of growth.
• Counting the rings on the trunk helps determine the tree's age.
• The study of tree rings is called Dendrochronology.

Last verified on 20-07-2026

Explanation

• Gregor Mendel is known as the Father of Genetics.
• He discovered the Laws of Inheritance through experiments on pea plants between 1856–1863.
• His research was published in 1866.

Last verified on 19-07-2026

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

• 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 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