Questions

Here Joystick, Mouse and Scanner are Input devices through which data is given to the computers. But Headphones are output devices through which sound comes as an output from the computer or any devices.

Plantain plant is a herb, because it does not have an aerial stem - what appears as a stem is really the leaves with sheathing bases. As the piant lives for several years it is called perennial herb

We know that polar substances are soluble in polar solvents and non polar substances are soluble in non-polar solvents only. Here the hydrocarbons are non-polar molecular substances and water is a polar solvent. So water can't dissolve hydrocabons.

Hence, as hydrocarbons are non-polar substances, they are insoluble in water as it is a highly polar solvent. 

Yes, a promise can be broken without being held.

GNLF stands for Gorkha National Liberation Front.

Gorkha National Liberation Front (GNLF) is a political party in the Darjeeling District of West Bengal, India. It was formed in 1980 by Subhash Ghisingh with the objective of demanding a Gorkhaland state within India.