The deficiency of vitamin B₁ causes: MCQ with Answer and Explanation

Explanation:
The BBB restricts entry of pathogens and large molecules, maintaining brain homeostasis. Tight junctions between capillary endothelial cells are the structural basis. R explains A.

Explanation:
Charles Darwin, an English naturalist, proposed the theory of evolution by natural selection in his seminal book 'On the Origin of Species' (1859). His theory, based on observations from his voyage on the HMS Beagle (especially the Galapagos finches), states that species evolve over time through the process of natural selection, where individuals with advantageous traits are more likely to survive and reproduce.

Explanation:
The glomerulus is a tuft of fenestrated capillaries enclosed by the Bowman's capsule in the renal corpuscle. Blood is filtered under high pressure through the capillary walls into the Bowman's space. The filtrate then passes into the nephron tubules. Glomerular filtration is the first step in urine formation.