Which device or set of devices is contained in a mobile telephone? need answer urgently if possible.

A. transmitter only

B. transmitter and receiver only

C. encoder and decoder only

D. encoder, transmitter, receiver, decoder

The sun generates both mechanical and electromagnetic waves. which statement about those wave is true?

Which of the following explains why it took so long for the public to accept the negative health effects of smoking? a)people were waiting for counter reasons, and those were presented.b)scientists had not completely finalized their results, which took 30 years.c)cigarettes were cheaply available and media channels were very inefficient.d)cigarette manufacturers were trying hard to bring an alternative into the market

Which of the following are used in an electrochemical cell? a. electrodes b. electrolyte c. terminals d. all of the above