• 11. Thinking about trophic levels, the type of energy we use from a natural resource comes through a transfer of what, which can also be classified as radiation?

Solar energy    

Explanation:

There are different kinds of energy, and one of them is radiation. By concept, radiation refers to the emission, propagation, and transference of energy in the form of electromagnetic waves or particles.  Living beings depend on solar energy from their origins.  

Throughout the trophic web, there exists a process of energy transference through the different trophic levels, in which every organism feeds on the preceding one and becomes food for the next one. Producers take solar energy and transform it into chemical energy, which is the one from one level to the other.  

Energy flow: From the whole quantity of solar energy that reaches the earth's surface, only 0.1 or 1% is absorbed by autotroph organisms or producers.    

From this input of solar energy, it begins a unidirectional energy flow through all the organisms in the ecosystem, from autotrophs to heterotrophs, until it is finally dissipated in the environment.  

At each trophic level, it occurs an energy transfer from one level to the next, with only 10% being usable in each of them. This assessment is called "The 10% rule". This is, as a general rule, only about 10% of the energy stored as biomass at one trophic level, per unit time, ends up as biomass at the next trophic level, in the same unit of time.

The progressive reduction of energy determines the number of trophic levels (4 or 5).