Consider the following statements about mitosis: 1. It produces diploid cells. 2. It is involved in growth and repair. 3. It reduces chromosome number by half. Which of the above is/are correct? MCQ with Answer and Explanation

Explanation:
John Gibbon developed the heart-lung machine and performed the first successful open-heart surgery using it in 1953. Barnard did first heart transplant.

Explanation:
Edward Jenner, in 1796, observed that milkmaids who had cowpox were immune to smallpox. He used material from cowpox lesions to inoculate a boy, who later proved immune to smallpox. This was the first successful vaccine. Rabies vaccine was developed by Louis Pasteur, polio vaccine by Jonas Salk, TB vaccine (BCG) by Calmette and Guérin. Smallpox has been eradicated globally.

Explanation:
Aspergillus niger is a fungus widely used for the industrial production of citric acid (a common food additive) through fermentation. Penicillium chrysogenum produces penicillin, Saccharomyces cerevisiae is used in baking and brewing, Rhizobium is a nitrogen-fixing bacterium. Citric acid is used as a preservative and flavor enhancer.