The deficiency of vitamin B₃ (niacin) causes: MCQ with Answer and Explanation

Explanation:
Imbibition is a physical process where solid, hydrophilic (water-loving) colloidal materials (like cellulose, pectin, proteins, and starch) adsorb water, causing a tremendous increase in their volume and generating significant imbibitional pressure. This process is the very first step in seed germination. When a dry seed is exposed to water, its cell walls and storage materials imbibe water, causing the seed to swell, rupturing the seed coat, and initiating the metabolic activities required for the seedling to grow. It is also responsible for the splitting of rocks by plant roots.

Explanation:
The stomach's gastric glands secrete hydrochloric acid (HCl), which creates an acidic environment necessary for the activation of pepsin and the initial digestion of proteins. The small intestine, with its vast surface area provided by villi and microvilli, is the primary site for the final digestion and absorption of most nutrients into the bloodstream. The liver is a large, multifunctional organ that continuously produces bile, which is stored in the gall bladder and released into the small intestine to emulsify fats. All statements are correct.

Explanation:
The Smooth Endoplasmic Reticulum (SER) lacks ribosomes on its surface and is primarily involved in the synthesis of lipids, including sterols and phospholipids. In liver cells, SER also plays a crucial role in the detoxification of poisons and drugs. Rough ER, which has ribosomes, is responsible for protein synthesis.