Questions

The nearest stars to Earth are in the Alpha Centauri triple-star system, about 4.37 light-years away. One of these stars, Proxima Centauri, is slightly closer, at 4.26 light-years.

Of all the stars closer than 15 light-years, only two are spectral type G, similar to our sun: Alpha Centauri A and Tau Ceti. The majority are M-type red dwarf stars.

Only nine of the stars in this area is bright enough to be seen by the naked human eye from Earth. These brightest stars include Alpha Centauri A and B, Sirius A, Epsilon Eridani, Procyon, 61 Cygni A and B, Epsilon Indi A and Tau Ceti.

A Light-year is a distance that light travels in the vacuum in one Julian year (365.25 days).

The light-year is a unit of length used to express astronomical distances. It is about 9.5 trillion kilometers or 5.9 trillion miles. 

The world’s largest tropical rainforest Amazon rain forests are called "Lungs of the Earth". It is so called because it produces 20% of the Earth's oxygen, and is also a vast carbon sink, absorbs more than 1 billion tons of atmospheric carbon which is emitted by the burning of fossil fuels annually.

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.

The lux (lx) is the SI derived unit of illuminance and luminous emittance, measuring luminous flux per unit area. It is equal to one lumen per square meter.