The chromosomal abnormality in Down syndrome is: MCQ with Answer and Explanation

Explanation:
The human skull consists of 22 bones (8 cranial and 14 facial). The femur (thigh bone) is the longest and strongest bone in the human body. Humans have 12 pairs of ribs; the first 7 are true ribs (direct attachment), next 3 are false ribs (indirect), and last 2 are floating. All statements are anatomically correct.

Explanation:
Lymph is interstitial fluid that has entered lymphatic capillaries. When lymph vessels are blocked (e.g., filariasis), lymph accumulates, causing swelling (lymphedema). Plasma is blood fluid, synovial in joints, serum is plasma without clotting factors.

Explanation:
The spleen is the largest organ in the lymphatic system. It plays a vital role in immune function by filtering blood, producing lymphocytes, and removing old or damaged red blood cells and platelets. The thymus is crucial for T-cell maturation but is largest in childhood and shrinks with age. Tonsils and Peyer's patches are smaller, localized lymphoid tissues. The spleen acts as a major blood filter and immune response center.