Bile juice is secreted by the: MCQ with Answer and Explanation

Explanation:
The Sinoatrial (SA) node, the natural pacemaker of the heart, is a small, specialized mass of autorhythmic cardiac muscle cells located in the upper wall of the right atrium, just below the opening of the superior vena cava. It spontaneously generates electrical impulses at a regular rate, which spread through the atrial myocardium, causing the atria to contract and push blood into the ventricles. The impulse then reaches the AV node.

Explanation:
Robert Hooke observed cork tissue in 1665 and coined the term 'cell' to describe the box-like structures. Matthias Schleiden, a botanist, concluded in 1838 that all plants are composed of cells, forming a core tenet of the cell theory. The cell nucleus was discovered by Robert Brown in 1831, not Antonie van Leeuwenhoek, who is famous for discovering living microorganisms. Thus, statements 1 and 3 are correct.

Explanation:
Photosynthesis is the anabolic process in which plants, algae, and cyanobacteria convert CO₂ and H₂O into glucose and O₂ using light energy, catalyzed by chlorophyll. Respiration breaks down glucose to release energy, fermentation is anaerobic breakdown, chemosynthesis uses chemical energy (in some bacteria).