Which of the following statements about the circulatory system is correct? MCQ with Answer and Explanation

Explanation:
Alveoli have a rich capillary network for O₂/CO₂ exchange. Inhalation is active (diaphragm contracts), trachea divides into two bronchi (not bronchioles).

Explanation:
Plasmolysis occurs when a plant cell is placed in a hypertonic solution, causing water to leave the cell by exosmosis, leading to shrinkage of the protoplasm and its detachment from the cell wall. Incipient plasmolysis is when protoplast just starts to pull away. Opposite is deplasmolysis (when placed in hypotonic solution). Swelling is turgidity. Animal cells undergo crenation or lysis.

Explanation:
Innate immunity is the non-specific defense mechanism present by birth, including physical barriers and phagocytes. Vaccination introduces antigens to stimulate the body's own antibody production, conferring artificial active immunity. Antibodies (immunoglobulins) are produced and secreted by B-lymphocytes (plasma cells), not T-lymphocytes, which are involved in cell-mediated immunity. Thus, statements 1 and 2 are correct.