Questions

Telnet uses TCP at layer 4. It uses IP at layer 3. We know that Telnet uses TCP/IP protocol, but in the question, it is asked specifically at layer 4 what is used in Telnet. So it is TCP at layer4 and IP at layer 3.

Light amplification by stimulated emission of radiation.

Lord Dalhousie was appointed as Governer General of India from 1848–1856. The first railway line connecting Bombay and Thane was laid under his authority in 1853 and is known as the maker of Modern India. He made way For Telegraph Services in India. 

He is also called as Father of Indian Railways.

Nutrients are necessary for break down the food and supply energy to the organisms and to carry out essential life functions.

• Important nutrients are Hydrogen, Carbon and Oxygen.

• Some more important nutrients for plants are : Potassium, Sulphur, Nitrogen, Phosphorous, Calcium and Magnesium.