The disease caused by the deficiency of thiamine (vitamin B₁) is: MCQ with Answer and Explanation

Explanation:
Rudolf Virchow, in 1855, added the third tenet to the cell theory: 'Omnis cellula e cellula', meaning all cells arise from pre-existing cells. Schleiden and Schwann proposed that plants and animals are composed of cells (first two tenets). Robert Hooke discovered cells. Virchow's concept refuted spontaneous generation and established the continuity of life.

Explanation:
Pulmonary ventilation is the mechanical process of moving air in (inspiration) and out (expiration), which is breathing. R correctly defines it.

Explanation:
Marasmus is a form of severe malnutrition caused by a deficiency of both calories and protein. It results in extreme wasting of muscle and subcutaneous fat, making the child look emaciated or 'wasted'. Unlike kwashiorkor, marasmus typically does not present with edema. The child is extremely weak, has a 'old man' face, and is highly susceptible to infections.