A
[2019·大连高三双基测试] Birds' feathers are some of the most strikingly variable animal characteristics that can be observed by eyes. The patterns that we see in birds' feathers are made up of combinations of scales, bars, and spots.
We already know why birds have colored feathers. For many birds, the color of feathers may make them less visible to the enemy by helping them match their surroundings, or more appealing to potential mates by helping them stand out. These aspects are well known. A greater mystery has been how the patterns are created.
Dr. Ismael Galván and his team of expert researchers studied the color of feathers to see what types of colors were present in birds' complex feather patterns. It turns out to be two types of pigments (色素) mainly: melanin (黑色素), which produces a range of black, grey, brown, and orange colors, and carotenoids (类胡萝卜素), which are used by specialized feather structures to create brighter colors.
Birds cannot produce carotenoids on their own. For feathers with bright colors, birds must consume food items that contain these pigments, and the carotenoids circulate through the bloodstream to the feather. Melanin, on the other hand, is produced in special cells in the birds' bodies.
This study was very large in scope, examining about 9,000 bird species, with the goal of supporting a general conclusion for all birds, to finally answer the question of how birds develop colorful and detailed patterns. If the birds were artists, they would use carotenoids as a broad brush to produce color patches, with melanin as a detailed paint brush to produce more complex designs.
A few birds are exceptions to this rule: Three bird families do have complex feather patterns without melanin: Fruit doves, cotingas and one type of stork.
体裁：说明文 题材：科学研究 主题：鸟类羽毛颜色
【语篇解读】 本文是一篇说明文，主要介绍了鸟类羽毛颜色是如何形成的。
【难句分析】 It turns out to be two types of pigments (色素) mainly: melanin (黑色素), which produces a range of black, grey, brown, and orange colors, and carotenoids (类胡萝卜素), which are used by specialized feather structures to create brighter colors.
分析：本句中包含两个which引导的定语从句，其先行词分别为melanin和carotenoids。
译文：结果主要是两种类型的色素：一种是产生一系列的黑色、灰色、棕色和橙色的黑色素，和被专门的羽毛构造使用来产生更鲜艳的颜色的类胡萝卜素。
1．What can birds do with their colored feathers?
A．Settle on right branches.
B．Fit in with their enemies.
C．Draw attention to possible mates.
D．Make birds invisible to their enemies.
答案与解析：C 考查细节理解。根据第二段第二句中的“more appealing to potential mates by helping them stand out”可知，鸟类羽毛的颜色能吸引可能的伴侣。
2．The colors and patterns of birds' feathers are mainly created by ________.
A．melanin and carotenoids
B．different types of pigments
C．special cells in the birds' bodies
D．combinations of scales, bars, and spots
答案与解析：A 考查细节理解。根据第三段的内容尤其是第二句“It turns out to be two types of pigments (色素) mainly: melanin (黑色素), which produces a range of black, grey, brown, and orange colors, and carotenoids (类胡萝卜素), which are used by specialized feather structures to create brighter colors”可知，鸟类羽毛的颜色和图案主要是由黑色素和类胡萝卜素产生的。
3．What can we know in Dr. Ismael Galván's study?
A．Melanin can produce a variety of bright colors.
B．Birds can create carotenoids in their own bodies.
C．Birds take food containing carotenoids to create bright colors.
D．Melanin and carotenoids are found in special cells of birds.
答案与解析：C 考查细节理解。根据第四段中的“Birds cannot produce carotenoids on their own. For feathers with bright colors, birds must consume food items that contain these pigments, and the carotenoids circulate through the bloodstream to the feather”可知，鸟类摄取含有类胡萝卜素的食物来产生鲜艳的颜色。
4．What does the author intend to do in the last two paragraphs?
A．Provide more examples for the readers.
B．Add some more background information.
C．Summarize the previous paragraphs.
D．Draw conclusions for the study.
答案与解析：D 考查推理判断。根据倒数第二段中的“This study was very large in scope, examining about 9,000 bird species, with the goal of supporting a general conclusion for all birds”以及最后一段第一句中的“A few birds are exceptions to this rule”可推知，最后两段是为该研究作结论。
