Read it through once

One might be disposed to think no more about these double coils; but here comes in one of the curious, inexplicable coincidences which happen so often in plant life. Such a coil is much stronger than a straight bit of wire or string would be, because if pulled out it yields and is springy. That of course makes it less probable that the tendril will be broken. Attached by a series of wiry springs, the plant yields and sways to the wind, and it is not likely that it will be torn away. Besides this, the coiling of the tendril pulls the stem closer to its support, which is also a great advantage.