The diagram is mainly about ______.

A．the food chain of the animal	B．the system of energy flowing
C．how to get food for man	D．the growth of the energy

Which is not the result of photosynthesis of the plant?

A．Oxygen is released into the air.	B．Food is provided for animals.
C．Certain forms of energy is produced．	D．The air is cleaned．

What occurs when the energy flows through the system?

A．Energy is consumed and one becomes the food of others.

B．Energy is stored and plants become animals.

C．Man plays an important part in energy flowing.

D．The more energy is consumed, the more energy the sun will supply.

What should be done in order to improve the living conditions according to the diagram?

A．More animals should be raised．	B．Decomposers should be made full use of.
C．More trees should be planted．	D．Man should be controlled．