The scientist who developed the oral polio vaccine was: MCQ with Answer and Explanation

Explanation:
The periderm is the outer protective covering of stems and roots that have undergone secondary growth (thickening), replacing the primary epidermis. It is composed of three distinct layers: 1) Phellem (cork): The outermost layer, consisting of dead, compactly arranged cells with suberized (waterproof) walls that provide protection and prevent water loss. 2) Phellogen (cork cambium): The middle, meristematic layer that produces phellem outwards and phelloderm inwards. 3) Phelloderm (secondary cortex): The innermost layer, consisting of living, parenchymatous cells.

Explanation:
The pitcher plant is an insectivorous (carnivorous) plant. Its leaves are modified into pitcher-shaped structures to trap and digest insects. This adaptation is primarily to supplement the plant's nitrogen intake, as it typically grows in nitrogen-deficient soils (like bogs). The digested insects provide essential nitrogenous compounds.

Explanation:
The ball and socket joint (e.g., glenohumeral, hip) allows movement in multiple axes (flexion, extension, abduction, adduction, rotation). The rounded head of one bone fits into the cup-shaped socket of another. Hinge (elbow, knee) allows movement in one plane, pivot (neck) allows rotation, gliding (wrist) allows sliding.