State the first law of thermodynamics and explain how living systems comply with this law. provide one real-life example to support your explanation.

The first law of thermodynamics states that the total energy of a system is constant. Energy can not be destroyed or created, it can only change forms. The energy in an ecosystem is constantly transformed into different forms, according to the needs of the living organisms. For example, plants absorb radiant energy from the sun and (through photosynthesis) they transform it into chemical energy which is kept in organic molecules.