They use photosynthesis to turn sunlight, carbon dioxide, and water into carbohydrates.
The reason why humming birds need long beaks is to be able to get the nectar from the flowers, kind of like how we need straws to drink out of to go cups. Humming birds also have very long tongues that also help this process. Since humming birds beaks help them get the food they need, it makes them more successful in their environment.
A difference between coelom and Pseudocoelom is that the gut of a pseudocoelom is surrounded by the endoderm, and the gut of a coelomate is surrounded by the ectoderm. So your answer is D.
