Question

multiple choice question
what is the ultimate source of energy for almost all living cells on earth?
the heat emitted by the earth after it is warmed up by the sun
the sun
the earths core
any kind of cosmic electromagnetic radiation that may enter earths atmosphere

Explanation:

Plants use sunlight for photosynthesis to produce energy - rich molecules. Other organisms obtain energy by consuming plants or other animals that have consumed plants. Thus, the Sun is the ultimate energy source for almost all living cells on Earth.

Answer:

The Sun