Which of the following blood vessels has the highest total cross-sectional area in the body? MCQ with Answer and Explanation

Explanation:
In plant tissue culture, when an explant (a piece of plant tissue) is placed on a nutrient medium containing specific plant hormones (like auxins and cytokinins), the cells dedifferentiate and undergo rapid, unorganized division to form a mass of cells called a callus. This callus is undifferentiated. Under appropriate hormonal conditions, this callus can then be induced to redifferentiate and form organized structures like shoots and roots (organogenesis) or somatic embryos.

Explanation:
Meiosis is reductional division occurring in germ cells to produce haploid gametes (n) from a diploid cell (2n). It involves two successive divisions (Meiosis I and II) and introduces genetic variation through crossing over and independent assortment. Mitosis maintains chromosome number, amitosis is direct division, and fission is asexual reproduction in prokaryotes.

Explanation:
Acid rain is caused by emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx) reacting with atmospheric water to form acids. Biological Oxygen Demand (BOD) measures the amount of oxygen required by microbes to decompose organic matter, indicating water pollution levels. Eutrophication (nutrient enrichment) causes algal blooms, depleting oxygen and killing aquatic life, thereby decreasing biodiversity. Thus, statements 1 and 2 are correct.