Seawalls are hard engineered structures with a primary function to prevent further erosion of the shoreline. They are built parallel to the shore and aim to hold or prevent sliding of the soil, while providing protection from wave action (UNFCCC, 1999).
Making the world better, one answer at a time. Vygotsky is best known for is theory of language acquisition, particularly the idea of scaffolding and the zone of proximal development.
In other words, social learning tends to precede (i.e., come before) development. Vygotsky has developed a sociocultural approach to cognitive development. He developed his theories at around the same time as Jean Piaget was starting to develop his ideas (1920's and 30's), but he died at the age of 38, and so his theories are incomplete - although some of his writings are still being translated from Russian.