Questions

Protecting data by copying it from the original source to a different destination is called as Backup. When an original data is lossed, to restore the information by copying the data from the source to other destination is called as Backup or Data backup.

Refractive Index of glass with respect to water can be calculated by 

(Refractive Index of glass with respect to air) × (1/Refractive Index of water with respect to air)

We know that,

Refractive Index of glass with respect to air = 4/3

Refractive index of water with respect to air = 3/2

Hence, Refractive Index of glass with respect to water = (4/3) x (2/3) = 8/9.

The pilgrims follow John Calvin's teachings.

Tropical rainforests are such rainforests that occur in the region of tropical rainforest climate where there is no dry season and it remain hot and wet.Tropical evergreen rainforest biome provides optimum environmental conditions for the growth of plants and animals because it experience heavy rainfall and high temperature, and extend between 10° N and 10° S latitudes. The biome Tropical rain forests are of mega thermal type because the organisms are adapted to high temperature and wet and humid condition. The maximum development of this biome has taken place in South America, lowland regions in Africa, and the islands off of Southeast Asia, Central America and parts of Australia.

The first talkie film in India was Ardeshir Irani released Alam Ara, on 14 March 1931.

Irani later produced the first south Indian talkie film Kalidas directed by H.M. Reddy released on 31 October 1931.

Cotton Gin was invented by Eli Whitney in 1793, which is used to separate cotton seeds from cotton fiber.

Hence, it was an important invention because it dramatically reduced the amount of time it took to separate cotton seeds from cotton fiber.

Brazil is one example of a closed economy in the given options. 

A closed economy is one that has no trade activity with outside economies. A closed economy is self-sufficient, which means no imports come into the country and no exports leave the country. A closed economy's intent is to provide domestic consumers with everything they need from within the country's borders.