The plants used 17440 Calories of energy.
Ellipse is your answer, because if you plug the equation into a graphing calculator and identify the conic, the term ellipse is given-
0.00067=67X10^5 so
67X10^5-2.3X10^5
64.7X10^5 which can be expressed as:
6.47X10^6
(not sure if it matters to you or not, but technically we only had two significant figures so it should be rounded to 6.5X10^6)
4/3
Remember if two lines are perpendicular, the product of their slopes are -1