Answer: The type of energy that we use from the natural resources comes through the transfer of solar energy.
Explanation: The energy from the sun is transferred to the producers, they covert the light energy or solar energy into chemical energy.
The energy is continuously used up in the ecosystem and is also added to the ecosystem by the producers. The energy is lost in the form of heat and it reaches the earth from sun in the form of solar radiation.
The energy in the ecosystem is lost in the form of heat at various trophic levels.
The producers transfers the energy to consumers and some of the energy is lost in the form of heat.
The flow of energy(radiation from sun to producers) in an ecosystem is continuous and its loss is also continuous in the form of heat.