4. Carla placed three identical plants on a
sunny windowsill. Using the same amount
of water each time, she watered one plant
twice a day. She watered the second plant
once a week. She did not water the third
plant. After three weeks, she found that the
plant watered once a week was thriving.
The plant that was watered twice a day
was dying. The plant that was not watered
was brown and dead. What conclusion can
Carla draw?
A. Water causes plants to die
B. Plants need a certain amount of water to live
C. Plants should not be placed on sunny windowsills
D. Plants do not live very long