Not a 100% sure but i believe it’s B
The control is the group of no fertilizers.
A control in an experiment is usually the group without the variable to be tested. In this case, the farmer wanted to test the effects of fertilizers, therofre the group without it is the control group.
Guard cells close up to prevent water loss. These guard
cells will automatically open up if there is a need of water to go out of the
cell. An open stomate allows water to leave through transpiration, guard cells
control the opening and closing of a stomata, stomates will close to reduce
water loss and By opening and closing the stomata on the underside of the
leaves.
