Consider statements about vitamins: 1. Vitamin B12 contains cobalt. 2. Vitamin K is essential for blood clotting. 3. Beriberi is caused by Vitamin C deficiency. Which are correct? MCQ with Answer and Explanation

Explanation:
The central vacuole occupies a large volume of a mature plant cell and stores water, creating turgor pressure against the cell wall, which maintains cell rigidity and plant structure. The cell wall provides mechanical support but turgor pressure generated by the vacuole is essential for maintaining turgidity, especially in herbaceous plants.

Explanation:
Collenchyma is a simple permanent tissue characterized by cells with thickened corners due to the deposition of cellulose and pectin. It provides mechanical support, tensile strength, and flexibility to the growing parts of the plant (like stems and petioles), allowing them to bend without breaking. Parenchyma is for storage, and sclerenchyma provides rigid support.

Explanation:
The juxtaglomerular apparatus (JGA) is a specialized structure where the distal convoluted tubule (DCT) comes into contact with the afferent arteriole. It consists of juxtaglomerular cells (modified smooth muscle cells in the afferent arteriole that secrete renin), macula densa cells (modified DCT cells that sense NaCl concentration), and extraglomerular mesangial cells. It plays a crucial role in regulating blood pressure and glomerular filtration rate via the renin-angiotensin-aldosterone system.