Answer
The increase in the number of plants shipped from February 2012 to April 2013 was $4,000$ plants.
Work Step by Step
The given graph shows the following information:
The number of plants shipped in February 2012 is around 5,500.
The number of plants shipped in April 2013 is around 9,500.
Thus, the increase in the number of plants shipped from February 2012 to April 2013 is:
$=9500 - 5500
\\=4000$