Answer:
the second law of thermodynamics. that some energy is destroyed in every energy conversion.
Explanation:
According to the second law of thermodynamics, energy conversion is never 100% efficient. Some energy is always lost as it is being converted from one form to the other.
The fact that a steer must eat at least 100 pounds of grain to gain less than 10 pounds of muscle tissue shows that not all the energy taken up from the grain is channelled towards building the muscle tissue. Some energy from the grains are lost on the way according to the second law of thermodynamics.
Answer:
Using lighter material in car construction, improving energy efficiency by enhancing engine design or replacing the engine with more efficient technologies.
Explanation:
Using lighter materials in the car construction, reducing the potential energy required to accelerate and to move the car, as well as energy losses due to rolling friction. There is evidence of such benefits by replacing steel and aluminium parts with components made of composite materials.
Improving the design of internal combustion engines to minimize energy losses and accordingly, improving energy efficiency. A more radical approach is replacing internal combustion engines with electric engines, which offer higher efficiencies. Such conclusions can be easily inferred from model based on Work-Energy Theorem and Principle of Energy Conservation:

A. Food chain
A food web also shows the flow of energy and materials through an ecosystem but in a complex web, not a single chain. A biogeochemical cycle does not deal with the flow of energy/materials through an ecosystem at all.
A hypothesis is an educated prediction that can be tested.