Questions

In India Coral Reefs can be found in Rameshwaram.

Coral reefs in India are one of the most ancient and dynamic ecosystems of India. The coral reefs not only provide a sanctuary to a myriad of marine life but also play a key role in protecting the coastline from erosion.

Coral reefs are diverse underwater ecosystems held together by calcium carbonate structures secreted by corals. Coral reefs are built by colonies of tiny animals found in marine water that contain few nutrients.

ptr pointer is constant. In ptr = yourbuf the program is trying to modify it, hence an error.

Because the refractive index of glass is highest, light travels slowly in Glass. 

We know that the speed of light depends on the refraction index. The higher the index of refraction is, the slower the speed of light is.

R.I of air and vacuum = 0 (air is a teeny bit more but can be taken as 0)
R.I of water = 1.33
R.I of glass = 1.4.

Hence, Light travels slowest in Glass.

DPI [Dots Per Inch] is a measurement of output quality of printer resolution. It represents number of ink dots the printer can place in an area of one square inch. The lesser the DPI the less sharper the image and vice versa.

Therefore, a printer that may have 400 DPI, a printer that can print 400 x 400 per square inch or 1,60,000 dots per inch.