One method of determining the level of blood flow through the brain requires the person to inhale air containing a fixed concentration of N₂O, nitrous oxide. During the first minute, the concentration of N₂O in the jugular vein grows at an increasing rate to a level of .25%. Thereafter, it grows at a decreasing rate and reaches a concentration of about 4% after 10 minutes. Draw a possible graph of the concentration of N₂O in the vein as a function of time.