Consider statements about vitamins: 1. Vitamin A is essential for vision. 2. Vitamin C is a fat-soluble vitamin. 3. Vitamin D deficiency causes rickets. Which are correct? MCQ with Answer and Explanation

Explanation:
Edward Jenner is considered the father of immunology for pioneering the concept of vaccination by developing the smallpox vaccine. Alexander Fleming discovered the first antibiotic, penicillin, from the fungus Penicillium notatum in 1928. Louis Pasteur made monumental contributions to microbiology and vaccination, but the structure of DNA was discovered by James Watson and Francis Crick in 1953. Thus, statements 1 and 2 are correct.

Explanation:
Meiosis I is the reductional division where homologous chromosomes separate, reducing the chromosome number from diploid (2n) to haploid (n). Meiosis II is equational division, similar to mitosis, separating sister chromatids. Thus, reduction occurs in anaphase I. DNA replication occurs in S phase before meiosis I. Gametes are haploid. Errors in reduction can lead to aneuploidy.

Explanation:
Urine specific gravity, a measure of solute concentration, normally ranges from 1.015 to 1.030. It varies with hydration status: low when dilute (after drinking), high when concentrated (dehydration). Diabetes insipidus shows low SG, diabetes mellitus may show high due to glucose.