Energy needs to be transformed into another form because in certain cases only this new form of energy is useful to us.
E.g. A power station burns coal (to make thermal energy)to heat up water which turns to steam (this has kinetic energy) and the steams passes through turbines which get spun by the steam. The spinning turbines create electricity which it transported to homes using the national grid and we can use it for our everyday home appliances.
We transform energy because we need it in a specific form - either for the end-user device (for example, for the radio, we want sound energy), or to transport energy from one place to another (electrical energy is quite useful for this purpose).
There WILL be energy transformations, whether we need it or not. Living beings, however, depend on energy transformation to live. We get energy from our food, which we "use up" and eventually convert to heat energy.
Radiation
I need more information
I am not entirely sure what you mean by "reversible by itself".An energy transformation is usually NOT entirely reversible. Some energy is wasted in the transformation, and (even though the energy is definitely still somewhere), you may need ADDITIONAL energy to transform it back.
Usually we need energy in some specific form, so we need to transform it from one type of energy to another.
We transform energy because we need it in a specific form - either for the end-user device (for example, for the radio, we want sound energy), or to transport energy from one place to another (electrical energy is quite useful for this purpose).
We don't always need the energy in the form in which it appears. For example, we humans can't directly use solar energy. Not even the plants use it directly - they need to transform it first.
There WILL be energy transformations, whether we need it or not. Living beings, however, depend on energy transformation to live. We get energy from our food, which we "use up" and eventually convert to heat energy.
Carbon monoxide usage is accelerating the rate of global warming; other forms of energy are "cleaner".
Fat cells have few mitochondria because they have little need for energy. Mitochondria transform glucose into energy.
Radiation
I need more information
because it breaks one of the laws of phisics and because nothing is something.
I am not entirely sure what you mean by "reversible by itself".An energy transformation is usually NOT entirely reversible. Some energy is wasted in the transformation, and (even though the energy is definitely still somewhere), you may need ADDITIONAL energy to transform it back.
We humans (as well as animals) get the energy we need from our food. This energy is stored in the food, in the form of chemical energy.
This requires magnets in general. It need not be an electromagnet; sometimes electromagnets are used, sometimes permanent magnets.