I believe the sunbird would benefit the plant because it would pollinate them. Going from flower to flower, pollen would get stuck on it's feathers and it would pollinate other flowers, like a bee.
im not positive but i think in the chemical bonds of molicules but id check google first
An enzyme, it catalyzes the reaction to convert carbon dioxide into carbonic acid
Explanation:
if you were trying to find the function of something it you would mainly think of roles, jobs, responsibilities, chores etc, where as if you were trying to find the structure it would be how something is made up or its form.
for example the srtucture of a plant, meaning its form or how it grew, its function depends on what type of plant, if it were just a regular plant or leaf, the stomata, cell wall, cell membrane, nucleus, chloroplasts, chlorophyll inside the chloroplasts, mitochondria, cytoplasm, would be requied to do their funtions i.e their jobs to keep the plant/leaf alive