Consider statements about human brain: 1. The cerebrum controls voluntary actions. 2. The cerebellum maintains balance. 3. The medulla controls breathing. Which are correct? MCQ with Answer and Explanation

Explanation:
Immunoglobulin G (IgG) is the most abundant antibody in human blood plasma, constituting about 75-80% of all antibodies. It is the only antibody that can cross the placenta, providing passive immunity to the fetus. IgG is crucial for long-term immunity, neutralizing toxins, viruses, and bacteria, and activating the complement system.

Explanation:
The loop of Henle creates a concentration gradient in the medulla, enabling water reabsorption and concentrated urine. Urine is formed in kidneys, the unit is nephron, ureter connects kidney to bladder.

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.