wheat
Most of the worlds oxygen is produced by Trees.
In PUNJAB most of Pakistan's rice is produced
panjab
Kansas produced the most wheat in 2008, but North Dakota produced the most in 2007, 2009 and 2010.
Kansas produced the most wheat in 2008 and 2011, but North Dakota produced the most in 2007, 2009 and 2010.
The most important crop would be wheat, followed by rice, corn and soybean.
Although wheat is grown in virtually every state, the focal point of the industry is in the central and southern Great Plains Region where Hard Red Winter Wheat is produced.
To me the answer to this question is starch
No , most of Protozoa are not photosynthetic hence can't produce O2 .
2012 World production of Grain was 2241million tons. China produced 479million tons. So, percentage terms; 21.3%
china is the largest producer of wheat