Which enzyme present in the stomach digests proteins? MCQ with Answer and Explanation

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.

Explanation:
Robert Koch established Koch's postulates, demonstrating that specific microbes cause specific diseases (anthrax, tuberculosis, cholera).

Explanation:
Frederick Griffith in 1928 demonstrated transformation by showing that heat-killed virulent pneumococci could transfer virulence to live non-virulent bacteria. Avery et al. later identified the transforming principle as DNA.