A. Loons
B. Grebes
C. Hummingbirds
D. None of these
Explanation:
They are the only bird species that can hover, and fly backwards, or even upside down. The ability to hover allows the hummingbirds to sip the nectar of plants and flowers. A hummingbird can’t walk or hop, but can shuffle with its extremely short legs, which are not very strong.