Who is known as the 'Father of Botany'? MCQ with Answer and Explanation

Explanation:
The sinoatrial (SA) node is a specialized cluster of cells in the right atrium near the opening of the superior vena cava. It generates electrical impulses spontaneously, setting the pace of the heartbeat, hence called the pacemaker. The impulse spreads to the atrioventricular (AV) node, then to bundle of His and Purkinje fibers. Normal SA node firing rate is 60-100/min.

Explanation:
Biofertilizers contain living microorganisms like bacteria, cyanobacteria, and fungi that increase nutrient availability (e.g., nitrogen fixation, phosphorus solubilization) for plants. They are eco-friendly and sustainable. Chemical fertilizers are synthetic inorganic salts. Biopesticides control pests. Examples: Rhizobium, Azotobacter, mycorrhiza. Biofertilizers improve soil health without chemical residue.

Explanation:
Vitamin B₁ (thiamine) is water-soluble and functions as a coenzyme (thiamine pyrophosphate) in carbohydrate metabolism, particularly in decarboxylation reactions. Vitamins A, D, E, and K are fat-soluble. B₁ deficiency causes beriberi and Wernicke-Korsakoff syndrome. Being water-soluble, excess is excreted in urine and toxicity is rare.