In the human body, the 'Medulla oblongata' is a vital part of the brainstem that controls involuntary functions such as: MCQ with Answer and Explanation

Explanation:
Antonie van Leeuwenhoek (1670s) constructed high-quality single-lens microscopes and was the first to observe bacteria, protozoa, sperm cells, and red blood cells, describing them as 'animalcules'. Hooke observed cells in cork. Pasteur disproved spontaneous generation, Lister introduced antiseptic surgery. Leeuwenhoek's pioneering work laid the foundation for microbiology.

Explanation:
Vitamin A (retinol) is crucial for the maintenance of the cornea and the synthesis of rhodopsin, a pigment necessary for vision in dim light. Vitamin C (ascorbic acid) is essential for the synthesis of collagen; its deficiency leads to scurvy, characterized by bleeding gums and poor wound healing. Vitamin K, not Vitamin D, is essential for the synthesis of prothrombin and other clotting factors. Vitamin D is essential for calcium absorption and bone health. Thus, statements 1 and 2 are correct.

Explanation:
The tracheal wall contains C-shaped hyaline cartilage rings that keep the airway open, preventing collapse due to negative pressure during inspiration. Smooth muscle and fibrous tissue connect the rings, ciliated epithelium sweeps mucus upward.