It was once believed that the sun was the essential energy source for all life, but it has been discovered that there is life dwelling in regions that receive no sunlight. For instance, the depths of the ocean. Therefore it can be concluded that some form of "food" or nutrient, whatever it may be, is the ultimate form of energy for life.
All living things require a source of energy.
glucose is the source of energy for all living things.
The sun
The sun
from the source of energy
The sun, respiration, photosynthesis and food are all sources of energy for living things.
The Sun.
The Sun :D
The sun and the sunlight are the main things for all living things.
Sunlight, and what they eat and the sun
Glucose
carbohydrates