Questions

Air or gas can build up in the pleural space and when this happens, it's called a pneumothorax.

Hence the given statement is TRUE.

Opposite means not identical, not same, not alike, contrast...

Here in the question, the opposite of the word opposite is asked and is opposite of not same , not identical or not alike is same, like, identical,...

The size of gear is usually specified by pitch circle diameter.

Satellites orbit the earth at a speed of 28,000 kmph.

Satellites that are further away actually travel slower. The International Space Station has a Low Earth Orbit, about 400 kilometers (250 miles) above the earth's surface. Objects orbiting at that altitude travel about 28,000 kilometers per hour (17,500 miles per hour).

Sublimation is a process when a solid changes directly into gas instead changing into liquid first. Dry ice is an example of Sublimation process because it doesn't change into liquid CO2 and directly change into gaseous CO2 when heated.

Hence, Dry ice is an example of Sublimation process. 

ICMP is Internet Control Message Protocol, a network layer protocol of the TCP/IP suite used by hosts and gateways to send notification of datagram problems back to the sender. It uses the echo test / reply to test whether a destination is reachable and responding. It also handles both control and error messages.