Someone please help.
A classmate designed a scientific investigation meant to determine whether plants release water vapor. She collects 40 similar plants, each growing in its own pot. She covers each plant with an individual plastic cup and leaves the plants overnight. Upon returning, she observes the inside of each cup contained droplets of water. She concludes that plants give off water vapor.

Being a science-minded individual, you have some critiques for your classmate. Name at least two possible flaws you see with this scientific investigation. For each, explain how it should have been done.