The element that is the central atom in the vitamin B₁₂ (cobalamin) molecule is: MCQ with Answer and Explanation

Explanation:
Inspiration (inhalation) occurs when the intra-pulmonary pressure is less than the atmospheric pressure. This is achieved by the contraction of the diaphragm, which flattens and moves downwards, and the contraction of external intercostal muscles, which lift the ribs and sternum. This increases the thoracic volume and lung capacity, drawing air in. Expiration involves relaxation of these muscles.

Explanation:
Proteins are complex macromolecules composed of long chains of amino acids linked by peptide bonds. Fats (triglycerides) are lipids composed of one glycerol molecule esterified to three fatty acid chains. Carbohydrates are composed of simple sugars (monosaccharides) like glucose, not fatty acids. Thus, statements 1 and 3 are correct, while statement 2 is false.

Explanation:
Photosynthesis, the process of converting light energy into chemical energy, occurs in the chloroplasts, specifically involving the thylakoid membranes and stroma. Cellular respiration, the process of breaking down glucose to release ATP, occurs primarily in the mitochondria. Transpiration is the loss of water vapor from plants, and while it can occur through lenticels (lenticular transpiration) and the cuticle, the vast majority (about 90%) occurs through the stomata (stomatal transpiration). Thus, statements 1 and 2 are correct.