There is no doubt that human activities have detrimental impacts on the environment and living organism habitants. While some people believe that there is nothing we can do to improve this situation, I believe it is never too late for us to make positive changes.
Admittedly, activities of humans have cost some influence that looks irreversible. That is to say either we cannot fix the problem based on our current technology level or it will cost too much of our society to make a change. For example, most transportation uses patrol as fuel which will cost enormous environmental pollution. However, society will not be able to function without it. In contrast, if human society stops all the activities that are harmful to the plants or animals, our society will stop progress once for all.
However, there are uncountable measures that can be utilised to preserve the species varieties. For instance, since the cloning of Dolly the sheep in 1996, scientists have known that DNA from a single cell can be used to produce an organism, which increases the possibility to resurrect the species that are extinct. Furthermore, raising the awareness worldwidely can cause significant changes. Ozone hole, the one of the most serious challenges in 21th century, as an example the global community worked on together, is expected to recover after the Montreal Protocol commits countries to phasing out all the ozone depleting substances in production.
In conclusion, although some damage caused is irreversible, together with global community and technology development, we can preserve more and more species. 
There is no doubt that human activities have detrimental impacts on the environment and living organism habitants. While  
some
  people
 believe that there is nothing we can do to  
improve
 this situation, I believe it is never too late for us to  
make
  positive
  changes
. 
Admittedly
, activities of humans have cost  
some
 influence that looks irreversible.  
That is
 to say either we cannot  
fix
 the problem based on our  
current
 technology level or it will cost too much of our  
society
 to  
make
 a  
change
.  
For example
, most transportation  
uses
 patrol as fuel which will cost enormous environmental pollution.  
However
,  
society
 will not be able to function without it.  
In contrast
, if human  
society
  stops
 all the activities that are harmful to the plants or animals, our  
society
 will  
stop
 progress once for all. 
However
, there are uncountable measures that can be  
utilised
 to preserve the species varieties.  
For instance
, since the cloning of Dolly the sheep in 1996, scientists have known that DNA from a single cell can be  
used
 to produce an organism, which increases the possibility to resurrect the species that are extinct.  
Furthermore
, raising the awareness  
worldwidely
 can cause significant  
changes
. Ozone hole, the one of the most serious challenges in  
21th
 century, as an example the global community worked on together, is  
expected
 to recover after the Montreal Protocol commits countries to phasing out all the ozone depleting substances in production. 
In conclusion
, although  
some
 damage caused is irreversible, together with global community and technology development, we can preserve more and more species.