Cardinal flower has scentless, bright red flowers that are long and tubular. What is the most likely pollinator of this plant?

Hummingbird

Explanation:

Pollination is the process by which pollen grains are transferred from anther of a flower to stigma. It is a vital process required for reproduction of new plants.

Cardinal flower has two upper petals and three lower spreading petals. All the petals combine to form a tube at the base. Hence the flowers get a tubular shape. Insects can not enter the tubular flower easily so humming birds usually pollinate these flowers. The hummingbirds feeds on its nectar and pollinates the flower in the process.