Acceleration of a body is defined as rate of chance in velocity with respect to time and its S.I. Units are
/ or 
Magnitude of average acceleration of a body = (final speed - initial speed)/time interval = 
where, final speed =v= 11 m/s; initial speed = u = 6 m/s; and time interval = t = 3 s
Hence acceleration =
=
= 
there are already many japanese plants, so not the iris. I don't see any water features here and I have no idea what a fence will do. Also I don't see a reason for a spirit gate, so the answer should be a water feature.