Final answer:
Ducks that patter along the water before takeoff are known as Dabbling Ducks. They can float despite their greater density than water because their feathers repel water and trap air, providing buoyancy and preventing them from getting wet. The correct option is A.
Step-by-step explanation:
Ducks that patter along the water's surface for some distance before take-off are known as Dabbling Ducks. These ducks are adapted to sit on the water's surface due to a phenomenon not related to vapor pressure, which affects objects like the novelty drinking bird toy.
Instead, dabbling ducks and other waterfowl such as geese and swans have a greater density than water but do not sink because their bodies are highly buoyant, and their feathers are coated with oils that repel water, preventing it from soaking them. This waterproofing capability, along with the air trapped in their feathers, allows them to sit comfortably on the water's surface.
Unlike soapy water, which reduces the surface tension of water, normal water supports ducks due to its higher surface tension that helps to keep the ducks afloat. This is why ducks struggle to stay on the surface of soapy water, as the reduced surface tension prevents their natural buoyancy from being effective.
Hence, Option A is correct.