The word for the process described in the question is 'pollination'.
Niche
Bees.
Its called 'interdependence.' The flowers need the bees to pollinate them to survive, but the bees need the flowers so they can make honey, and the female bees pollinate flowers and keep pollen on there legs to feed there larve.
Bees pollinate the flowers.
Bees pollinate flowers.
Bees of all varieties pollenate flowers, but not all bees do so. This may seem a contradiction, but only the worker bees pollinate, not the queens or drones.
Yes, honey bees can pollinate plants other than flowers. For example, in California, honey bees are absolutely essential to pollinate the almond trees.
bumble bees
no
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bees pollinate them
If your question is do they, the answer is yes. All flowers are good for bees.