Almost every part of a bird's anatomy has evolved ...

Question

Almost every part of a bird's anatomy has evolved in some part to enhance flight. Birds must be lightweight to fly. So that birds have evolved very lightweight hollow bones. The structure of their bones resembles honeycomb, making them very strong but also very light.

The most obvious adaptations for flight are bird's wings. To flap their wings and provide power for flight, birds contract their large pectoral (breast) muscles which are anchored to a keel on their sternum (breastbone). Many birds, such as birds of prey use air currents to soar and glide, whereas birds such as hummingbirds must flap continuously to hover while feeding. Some birds have evolved into flightless birds, in the absence of natural predators or in the case of penguins, to enable them to swim. In all birds capable of flight, it is the shape and arrangement of feathers which enables them to create lift with their wings.

Feathers are remarkably light and strong. They are composed of keratin, which is the same protein that makes up our hair and nails, as well as the scales of reptiles. A feather consists of a central hollow shaft, rather like a tree trunk. The shaft has vanes which radiate from it like the branches of a tree. The vanes are known as Barbs, and from these radiate barbules, similar to the smaller branches of a tree. Barbules have hooks which cling to barbules on neighbouring barbs, like a tree with entangled smaller branches. When birds preen, they run the length of the feather through their bills, which engages the hooks and shapes the barbs into a vane. The arrangement of the preened feathers enables the birds' wings to be airfoils, "structures whose shape creates lift by altering air currents" (Campbell and Reece, 2002). As a result of this shape, the air pressure pushing down on the wing is less than the air pressure pushing upward on the bottom of the wing. The difference in pressure provides the "lift" for flight.

Adapted from: birdsinbackyards.net

How does the writer give the opinion about feathers?

N. Nadzifah · Accepted Answer

Hai Lala! Kakak bantu jawab, ya.

Jawabannya adalah "The writer thinks that the feathers are remarkably light and strong."

Yuk, kita bahas!

Soal menanyakan pendapat penulis mengenai bulu burung.

Menurut penulis, bulu burung itu ringan dan kuat. Hal ini diketahui dari kalimat "Feathers are remarkably light and strong." Artinya, "Bulu burung itu ringan dan kuat."

Jadi, jawabannya adalah "The writer thinks that the feathers are remarkably light and strong."

Mau pemahaman lebih dalam untuk soal ini?

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