Janet and Ahmad are both doing a science project about growing grass. They both sprinkle grass seed on a box of soil
10 cm by 15 cm by 5 cm deep. They plant their grass seed on the same day. They water the seeds with 50 mL of water
every other day. After four days, the grass seed sprouts. After three weeks, Ahmad's grass is 2 cm taller than Janet's.
What might account for the difference in growth rates?
