1. 2 way radio
2. radio waves
3. communication
4. convert the voltage from a transmitter into a radio signal
5. signal strength refers to the transmitter power output
6. sorry, not so sure.. Though it might be the waves.
8.1) Here, Pressure increases with depth in the ocean at higher rate then that of increase in altitude in atmosphere. So, the rate of change of pressure is different in these journeys.So, your most correct answer would be option D.
8.2) Difference in the shape of lines is due to different density of air & water. So, that physical property and your answer would be option A
So, in Short Answers of your questions are:
8.1) - Option D
8.2) - Option A
Hope this helps!
It is actually caused by the environment, so its false. :)