Sugar(glucose) and oxygen.
LOCAL ENVIRONMENT ISSUE:
People dump a lot of trash in the sea, and the sea creatures living there goes through a lot of trouble to live with all the muck getting in them. Of course, don't write it like that in your assignment - you'll get told off for the straight forwardness.
The reason for governments to intercede in the market is to insure there is regulation and no black market trading or selling occurring
with this, the government will create an equal opportunity for everyone to enter the market
Hope this helps