Answer:
Positive feedback system increases temperature of the earth surface which is good in a number of ways.
Explanation: For example, due to increase in the temperature of earth surface, melting of ice occurs in the mountainous area of the world. This stored form of water is changed into liquid form and flows down through streams and used by plants and animals. But more increase in temperature causes rise of sea level which is not good for areas near the sea.
I think 75% or 90% (I looked it up lol)
The answer to the question mentioned above is the "Chloroplast".
During the light-dependent reaction of photosynthesis, chloroplast is decomposed to supply hydrogen ions tp produce NADPH, and important energy-carrying molecule used to help produce glucose during the light dependent reaction.