Questions

A relational database is a digital database based on the relational model of data, a database structured to recognize relations between stored items of information. A software system used to maintain relational databases is a relational database management system.

Computer database in which all data is stored in Relations which (to the user) are tables with rows and columns. Each table is composed of records (called Tuples) and each record is identified by a field (attribute) containing a unique value. Every table shares at least one field with another table in 'one to one,' 'one to many,' or 'many to many' relationships. These relationships allow the database user to access the data in almost an unlimited number of ways, and to combine the tables as building blocks to create complex and very large databases.

Internet service providers (ISP's) emerged in the late 1980's and early 1990's.

The ARPANET was decommissioned in 1990.

By 1995, the Internet was fully commercialized in the U.S., when the NSFNet was decommissioned, removing the last restrictions on use of the Internet to carry commercial traffic.

Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations.

In the form of vinegar, acetic acid is known from very early times. It is got by oxidation of fermented liquors (10-15%, alcohol) by air under the influence of a bacteria called 'mycoderma acetic'

The ball with which Table Tennis is played is called Ping Pong Ball.

According to the International rules, the diameter of the ping pong ball must be not less than 39.5 millimeters and not greater than 40.5  millimeters having a mass of 2.7 grams.

The water cycle is a term for the movement of water between the Earth's surface, the sky and underground. Water evaporates due to heat from the sun. Hence, the water cycle is driven primarily by the energy from the sun.

This solar energy drives the cycle by evaporating water from the oceans, lakes, rivers, and even the soil. Other water moves from plants to the atmosphere through the process of transpiration.