According to most scientific models, how many years ago did the first simple cells appear on earth? a) 400,000 b) 4 million c) 400 million d) 4 billion

answer; ///the correct answer to the above question is (

the most common energy conversion is from kinetic energy to potential energy, and then from potential energy to kinetic energy.

later on comes the heat energy, mechanical energy, and other energy conversions.

this energy conversion is so common that we can find it in our day to day lives as well.

- one of the most common energy conversions involves the changing of potential energy to kinetic energy or kinetic energy to potential energy