Which of the following vitamins acts as a crucial coenzyme in carboxylation reactions and is synthesized by beneficial bacteria in the human gut?

💡 Solution & Explanation

Vitamin B7, commonly known as biotin, functions as an indispensable prosthetic group and coenzyme for multiple carboxylase enzymes driving key metabolic pathways like gluconeogenesis. Other options such as ascorbic acid act primarily as antioxidants and cofactors in collagen synthesis rather than serving as carboxylation coenzymes. Dietary deficiency of biotin can lead to dermatitis and neurological symptoms in humans.