The part of the human digestive system where most chemical digestion and absorption occurs is the: MCQ with Answer and Explanation

Explanation:
The vermiform appendix is a vestigial organ, reduced in size and function, serving no essential digestive role in humans. Other vestigial structures include wisdom teeth, ear muscles, and coccyx. They are remnants of organs that were functional in ancestors, providing evidence for evolution. Heart, lung, and kidney are vital functional organs.

Explanation:
Poliovirus attacks motor neurons in the spinal cord and brainstem, causing paralysis. It spreads via the fecal-oral route. Vaccination (IPV/OPV) has almost eradicated it globally. The virus replicates in the intestine and then invades the nervous system. Polio survivors may suffer post-polio syndrome later.

Explanation:
Calcium ions (Ca2+) are essential cofactors in the blood coagulation cascade, required for converting prothrombin to thrombin. Iron is the central atom in the heme group of hemoglobin, enabling oxygen transport in red blood cells. Iodine is an indispensable component of the thyroid hormones thyroxine (T4) and triiodothyronine (T3). All three statements are biologically accurate.