Chlorophyll in green plants trap light energy from the sun and produces chemical energy in the form of glucose during photosynthesis.Consumers{ carnivorous or herbivorous animals } absorb this energy through feeding relationships in the food chain or food web. Glucose is used in all organism to produce energy during respiration for muscle contraction, cell division, active transport etc. thus, the light energy that originated from the Sun is passed along the food chain as chemical energy. Therefore, because of light energy, The Sun is the principle source of energy for all living organism.

(b) non cycle flow of energy
Non-cyclic flow of energy refers to the light energy from the sun that is trapped by the Producers and transfered to the consumers in the form of chemical energy. this energy is eventually lost to the environment as heat loss because during respiration, some of the energy realised is changed into heat enegy and heat energy cant be changed by living things into chemical energy.

(c) Relationships in the food web
- producers
green plants that produces energy for other living organism to survive by changing light energy into chemical energy in the form of glucose. this glucose is changed into other forms{eg fats or proteins} which contain chemical energy is eat and passed down the food chain.

-Consumers
animals cannot photosynthesize. animals cannot make food. Since animals cannot make food, they take food that is made by other living organism in order to survive. They realease chemical energy in food during respiration in order to survive and reproduce.

-Decomposers
example of decomposers are bacteria and fungi. they break down organic compound in dead remains and release raw materials such as carbon dioxide and mineral salts back to the environment.

(d)reasons for energy loss
- not all part of the plant is eaten
-The plant is respiring{ some energy is lost as heat enery}
-The plant might not be digested.
-Excretion{ removal of metallbolic waste}

Part 2 later. man, ecology is pretty hard to memorise. \:
Jiayous ! last chap !

At every level, about 90% of the energy is lost. that is why a food chain cannot have more than 6 links. this is because the last population would have too little energy to support another population to grow and reproduce.