Answer: D) None of the above
Explanation: The subschema differs from the schema in that one denotes the appearance of data in the Database Base Management System (DBMS) while the subschema which is also referred to as the external schema is that subset of the schema is visible or relevant to the user. Thus, It is the view of the database which is visible to an application program. Virtual tables in a database usually represents an object structures like a table which is the result of running certain database commands or functions such as the create table, view, select and so on. Virtual tables are not stored directly in database files.
Answer:
Because of their wave movement, P waves travel through any kind of material, whether it is a solid, liquid or gas. On the other hand, S waves only move through solids and are stopped by liquids and gases. ... This also accounts why fewer S waves are recorded than P waves.
Canada: H
Alaska: P
US: H
Cuba: P
EU: H
Canada: P
Hawaii: H
DescriptionIguazú Falls or Iguaçu Falls are waterfalls of the Iguazu River on the border of the Argentine province of Misiones and the Brazilian state of Paraná. Together, they make up the largest waterfall system in the world. The falls divide the river into the upper and lower Iguazu.
Iron was able to show previous orentations of earth's magnetic field
