The largest part of the human brain is the: MCQ with Answer and Explanation

Explanation:
The aorta receives blood directly from the left ventricle under high pressure (systolic ~120 mmHg). Pressure decreases as blood moves through arteries, capillaries, and veins. Vena cava pressure is near zero.

Explanation:
Mitochondria produce ATP through oxidative phosphorylation in the inner membrane. They are double-membrane organelles with their own DNA (mtDNA) and 70S ribosomes, supporting the endosymbiotic theory. The Krebs cycle occurs in the mitochondrial matrix. Nucleus controls cell activities, ribosomes synthesize proteins, Golgi apparatus packages and modifies proteins. Mitochondria are abundant in energy-demanding cells like muscle cells.

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.