57.Moreover，the degree to which cones are naturally slightly open or tightlyclosed helps determine which bill design is the best．

(句子主干是the degree…helps determine…，从句to which cones are naturally slightly open or tightly closed作degree的定语)

而且球果自然地轻微开口或紧紧关闭的程度有助于确定哪种喙的设计是最好的。