The scientist who published 'On the Origin of Species' is: MCQ with Answer and Explanation

Explanation:
The Casparian strip is a band of cell wall material that runs radially and transversely through the cell walls of the endodermal cells in plant roots, but is absent from the tangential walls. It is primarily composed of suberin (a waxy, waterproof substance) and lignin (a complex polymer). This strip acts as a physical and chemical barrier, blocking the passive, apoplastic flow of water and dissolved minerals between the cells. It forces these substances to cross the selectively permeable plasma membrane and enter the symplastic pathway, allowing the plant to control what enters the vascular cylinder.

Explanation:
Mature human RBCs have a lifespan of approximately 120 days, after which they are phagocytosed by macrophages in the spleen and liver. They lack nuclei and organelles, thus cannot repair themselves. New RBCs are produced in the bone marrow at a rate of about 2 million per second. Erythropoietin stimulates RBC production.

Explanation:
Cotyledons are seed leaves that store food (starch, proteins, lipids) for the developing embryo and may become photosynthetic after germination. Monocots have one, dicots two. Radicle is root, plumule shoot, seed coat protects.