The direct consumption of algae as human food is widely practiced around the world. A list of more than hundred species can be made which provide direct food to the human beings, especially to the coastal people of the world.
Auxins are powerful plant growth hormones (or plant growth regulators) produced by plants. They are found in the shoot and root tips and promote cell division, stem and root growth. Auxins are involved in phototropism, geotropism, hydrotropism and various other developmental changes.
The Mesozoic Era spans from about 252 million years ago to about 66 million years ago that means it began roughly around the time of the end-Permian extinction. The amphibians were declining after a long period of supremacy among the animals and the reptiles were gradually replacing them. Many of them became very large fearsome and came to dominate the animal life practically everywhere and spread into all habitats. For this reason, the Mesozoic era is also called the Age of Reptiles or the Age of Dinosaurs.
Like the development of the flagellum for movement, sexual reproduction in protists involving meiosis, syngamy and zygote formation appears to have been a major evolutionary innovation by the primitive protists. This innovation has made a profound effect on more complex organisms.