Questions

The Good Governance Day (GGD) is observed every year in India on the eve of the birth anniversary of former Prime Minister Atal Bihari Vajpayee.

Salivary glands of man are  3 pairs = 6. They are one pair of parotid glands, one pair of sub-maxillary or sub-mandibular glands and one pair of sub-lingual glands.

Epiglottis is that prevents food from entering the windpipe. 

It is a cartilageous flap that flaps opens and closes when swallowing. When you swallow, the epiglottis flattens backward to cover the entrance to your larynx and prevent food from entering the lungs and windpipe. The epiglottis returns to its usual position after swallowing.

C++ is not an Operating System.

An Operating System is a collection of system programs that manages all the other programs application programs in a computer as well as the allocation and use of hardware resources such as the CPU, Memory and the Hard Disk Drive.

It acts as an interface between the hardware and the user level program.

It controls and facilitates the overall operation of a computer. 

Here

UNIX : UNIX is a popular multi-user, multitasking operating system (OS) developed at Bell Labs.

Windows NT : Windows NT is a family of operating systems produced by Microsoft, the first version of which was released in July 1993.

DOS : DOS is Disk Operating System. The term DOS can refer to any operating system.

C++ : C++ is a programming language and computing platform.

Hence, C++ is not an Operating System.