The best answer would probably be observation because a hypothesis and theory is not always reliable. an observation describes what IS happening during the experiment.
Answer:
They are adapted for photosynthesis by having a large surface area, and contain openings, called stomata to allow carbon dioxide into the leaf and oxygen out. Although these design features are good for photosynthesis, they can result in the leaf losing a lot of water. The cells inside the leaf have water on their surface. Some of this water evaporates, and the water vapour can then escape from inside the leaf.
Nerves - transmit impulse of sensation to brain or spinal cord, then to muscles and organs
I believe it is A. Nerve. I am pretty positive I am right.
