Question

How long does Algae take to grow?

Answer 1

Hint: Algae are the members of polyphyletic clades which are from the photosynthetic eukaryotes. Algae have the same fragmentation and cell division. Algae reproduction is done through regeneration which is under sexual methods. Usually, algae reproduce by both sexual and asexual methods but the average time algae take to grow is- $30$ days to $4$ weeks.

Complete answer:
Algae grow quickly if provided proper nutrients and habitat while sometimes it depends on species to species. Microalgae can grow double to the size of normal algae and in less than $24$ hours. Other algae-like-macroalgae called as seaweed are mostly marine and have normal size in growth.
By providing plant fertilizer in a particular culture where algae are growing, the fertilizer can provide more nutrients in algae growth and also factors like-sunlight, water, chlorophyll, carbon dioxide are needed like any other green plant. Algae produce their own energy just like other plants- they make their own glucose.
Lifespans of algae can be one to two years depending on species. Many algae species reproduce by ordinary cell division algae which are small in structure and algae which are larger will undergo spore formation for reproduction. Examples- red algae producing monosporic cells which are red in color, have spherical shape and non-flagellate.
Some green algae produce aplanospores which are similar like- other spores. Zoospores are produced by other algae that lack cell walls and possess more flagella. These spores are mostly carried by water currents and also by air medium and start growing where they land.

Note:
Algae are being grown because they possess high economical importance such as- food sources, fodder in fish farming and even as a fertilizer. Also plays a role in alkaline reclaiming and soil binding agent. Also, algae can be used as organic food molecules which traps energy from sunlight. They are estimated from $30 - 50$ percent of oxygen availability globally.