The diagram represents the cycle in which Biodiesel is produced.
Overall, the process consists of four major stages، begining with biosynthesis and ending up with transestrification reaction.
First of all, sunlight is harnessed by oil crops to perform photosynthesis for Biodiesel manufacturing. After that, seeds of main crops are harvested in order to extract crude vegetable oil from them, transferred to the next step of the process. The liquid is undergone refinement and further purified which refined vegetable oil produced. Following this, The product and added alcohol into the reaction ambiance will experience chemical transesterification procedure. Subsequently, as a result of this reaction biodiesel as well as a by-product called glycerol are created, that is useful for food industry and beauty products.
In the next stage, Biodiesel is utilised for vehicle's fuel purposes. Finally, through running these machines will be generated energy as well as emitted CO2 which is absorbed by oil crops so that this cycle is repeated. 
The diagram represents the cycle in which Biodiesel  
is produced
. 
Overall
, the process consists of four major  
stages،
  begining
 with biosynthesis and ending up with  
transestrification
 reaction. 
First of all
, sunlight  
is harnessed
 by  
oil
 crops to perform photosynthesis for Biodiesel manufacturing. After that, seeds of main crops  
are harvested
 in order to extract crude vegetable  
oil
 from them, transferred to the  
next
 step of the process. The liquid is undergone refinement and  
further
 purified which refined vegetable  
oil
 produced. Following this, The product and  
added
 alcohol into the reaction ambiance will experience chemical  
transesterification
 procedure.  
Subsequently
,  
as a result
 of this reaction biodiesel  
as well
 as a by-product called glycerol  
are created
,  
that is
 useful for food industry and beauty products.
In the  
next
 stage, Biodiesel is  
utilised
 for vehicle's fuel purposes.  
Finally
, through running these machines will  
be generated
 energy  
as well
 as emitted CO2 which  
is absorbed
 by  
oil
 crops  
so
 that this cycle  
is repeated
.