Explanation:Water blooms are often the result of rapid growth and accumulation of blue-green algae (cyanobacteria), which can produce toxins and deplete oxygen levels in water bodies.

Explanation:Spirogyra is commonly referred to as ‘Pond silk’ or ‘Water silk’ due to its filamentous and slimy nature, which resembles silk threads floating in water.

Explanation:Scalariform conjugation is the most common type in Spirogyra, where adjacent filaments align and form conjugation tubes for the exchange of genetic material.

Explanation:Laminaria, a type of brown algae, is a significant source of iodine, which is extracted for various uses, including dietary supplements.

Explanation:Cap cells are characteristic of Oedogonium filaments, where they appear at the ends of cells and play a role in cell division and growth.

Explanation:C. brauni exhibits anisogamous sexual reproduction, where the gametes are dissimilar in size and form, with one being larger and non-motile, and the other smaller and motile.

Explanation:Heterocysts are specialized nitrogen-fixing cells found in some cyanobacteria, such as Nostoc, which provide an anaerobic environment for the enzyme nitrogenase to function.

Explanation:Spirogyra is notable for its spiral-shaped chloroplasts, which are a unique feature among algae and aid in photosynthesis.

Explanation:Blue-green algae (cyanobacteria) and certain bacteria possess the ability to fix atmospheric nitrogen through specialized structures called heterocysts, contributing to the nitrogen cycle in ecosystems.

Explanation:The stigma, or eye spot, in Chlamydomonas is a light-sensitive organelle located at the anterior end of the cell, helping the organism to detect and move towards light sources.