While no one knows why, astronomers do now know that long ago the solar nebula gained gravity deacreased in size increased in size collapsed

The experiments with static charges were done by:

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

Use 4 to 5 complete sentences, explain the concepts of beats and how beats are produces.