Directions: In the question below, the 1st and the last (correctly ordered) sentences are numbered 1 and 6. The rest of the passage is split into four parts and named P, Q, R and S. These four parts are not given in the proper order. Choose the correct combination among the four alternatives given.
- An early method of cooling air as practiced in India was to hang wet grass mats over windows where they cooled incoming air by evaporation.
P. In the beginning of 20th century, Carrier devised an air-conditioning unit based on the principle that cooled air reaches saturation and loses moisture through condensation.
Q. The first fully air-conditioned office building, the Milam Building in San Antonio, Texas, was constructed in the late 1920s.
R. Modern air-conditioning had its beginnings in the 19th-century textile industry, in which atomized sprays of water were used for simultaneous humidification and cooling.
S. Carrier also devised a system wherein conditioned air was fed from the ceiling and exhausted at floor level.
- The development of highly efficient refrigerant gases of low toxicity known as Freons in the early 1930s was an important step.