The release of an ovum from the ovary is termed: MCQ with Answer and Explanation

Explanation:
Magnesium (Mg²⁺) is the central atom in the porphyrin ring of chlorophyll, crucial for light absorption. Iron is in hemoglobin.

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.

Explanation:
Xylem is a complex permanent tissue responsible for the unidirectional upward transport of water and dissolved minerals from the roots to the aerial parts of the plant. Phloem is the vascular tissue responsible for the translocation of organic nutrients (primarily sucrose) from sources (leaves) to sinks (roots, fruits), which can be bidirectional. Cambium (vascular and cork) is a lateral meristem responsible for secondary growth (increase in girth); primary growth (increase in length) is driven by apical meristems. Thus, statements 1 and 2 are correct.