Questions

The common greenhouse gas containing only hydrogen and oxygen is H2O, this is water vapor.

The common greenhouse gases are water vapor, carbon dioxide, methane, nitrous oxide, and ozone.

The composition (chemical formula) of those gases are:

Water vapor: H2O
Carbon dioxide: CO2
Methane: CH4
Nitrous oxide: NO
Ozone: O3.

As you see the only one of those that contains only hydrogen and oxygen is H2O, water vapor.

One grandfather, One father and One son makes two fathers and two sons.

This region is thus called because of its rich coal field and the iron and steel plants that have come up around them. Rhur valley is a major Industrial hub of West Germany. 

Blotting paper absorbs ink by the process of capillary action. The capillary action is based on the property of surface tension of liquid.

All unsized paper will absorb water. Blotting paper is not sized and made bulkier to provide capillary action for faster absorption of liquid.

Blotting paper has also been sold as a cosmetic to aid in the removal of skin oils and makeup.

PARAM 8000 was was the first supercomputer developed by Indian scientists launched on July 01, 1991 is considered India's first supercomputer.

• It was indigenously built in 1991 by Centre for Development of Advanced Computing and was replicated and installed at ICAD Moscow in 1991 under Russian collaboration.