Is the current method of commercial wheat farming in the Great Plains sustainable?

The sun's parallax would be 180 degrees, greater than which you can't get.  so a. would be your anwser 

It would be tomatoes i believe

When a lake, river or other aquatic  system  becomes  eutrophic, it can have serious negative effects on other organisms like fish, birds and even people.if an algal bloom is so bad that it causes wide-spread death  in  the  water, the organisms that die will all sink to the bottom and start to decompose.