Questions

Daemon is a program that runs in the background without user’s interaction. A daemon runs in a multitasking operating system like UNIX. A daemon is initiated and controlled by special programs known as ‘processes’.

Secondary pollutants include ozone, which is formed when hydrocarbons (HC) and nitrogen oxides (NOx) combine in the presence of sunlight.

Whereas Primary pollutant are those pollutants that are directly emitted from their sources, like CO2, CO, SO2 as these gases are directly emitted form burning of fossil fuels.

Acid rain, which is formed when sulfur dioxide or nitrogen oxides react with water, sulfuric acid etc.

Hence, Acidrain is a secondary air pollutant.

Mumps : This is a swelling caused by information of parotid glands placed in front of our ear region. The inflammation is caused by a virus.

In chemistry, the term transition metal has three possible meanings: The IUPAC definition defines a transition metal as "an element whose atom has a partially filled d sub-shell, or which can give rise to cations with an incomplete d sub-shell".

Any of the set of metallic elements occupying a central block (Groups IVB–VIII, IB, and IIB, or 4–12) in the periodic table, e.g. iron, manganese, chromium, and copper. Chemically they show variable valency and a strong tendency to form coordination compounds, and many of their compounds are coloured.

Here in the given options, only iron (Fe) is a transition metal since Strontium is an alkaline earth, arsenic is a metalloid, hydrogen is (normally) a diatomic gas.

Hubs regenerate electrical signals, which are specified at the Physical layer.

We know that, the collection of programs which performs specific tasks in a computer is called as software. Software in a computer is of two types. They are :

1. Aplication Software

2. System Software

System software is a computer program that performs the basic functionaility of a computer i.e, running a systems hardware and applications like loading programs, saving data, displaying, etc...