Answer: Lymphatic system
Explanation:
Not respiratory and excretory for sure.
Not nervous because the diagram doesn't show spinal nerves clearly. So its lymphatic system.
:-)
Answer: chain link fence
Peptidoglycan could be found in high number on gram positive cell walls. The structure of peptidoglycan looks like a cross link which makes it sturdy, so rain coat would be false. It is not an impenetrable brick wall because it still allow some ion and food pass through it. Sugar candy coat sounds good but chain link fence would be better.
there would be no ecosystem
D) A & B
it protects the seed against any damage or harmful weather conditions and also helps in dispersal of the seed through different means.