互花米草（Spartina）为湿地生态系统提供关键支撑，不仅为昆虫、鸟类和动物提供食物来源，还通过其地下茎传播形成密集群落。它能在从沙质到砾石的不同基质上生长，耐受从淡水到海水的各种盐度，特别能通过叶片表面的盐腺去除体内多余盐分。然而，在新西兰，互花米草的快速扩张改变了潮间带环境，将泥滩转化为广阔的盐草甸，减少了使用该湿地的鸟类和动物种类。
Numerous insects occupy the marsh, feeding on living or dead cordgrass tissue, and red wing blackbirds, sparrows, rodents, rabbits, and deer feed directly on the cordgrass.
A. Insects feed only on dead cordgrass, while most other marsh inhabitants feed on live cordgrass.
B. The marsh is a good habitat for insects, but a relatively poor one for birds and animals.
C. Although cordgrass provides food for birds and animals, it gives insects both food and a place to live.
D. Cordgrass provides food for numerous insects, birds, and other animals.
A. It makes a general claim about Spartina and then provides specific evidence to defend that claim against objections to the claim.
B. It presents a general characterization of Spartina and then describes particular features on which this characterization is based.
C. It reports a widely held view about Spartina and then considers evidence both for and against that view.
D. It presents a general hypothesis about Spartina and then lists specific evidence that disputes that hypothesis.
事实还是假说 是否有反对
Highly very exceedingly
a highly successful politician
It spreads primarily by underground stems; colonies form when pieces of the root system or whole plants float into an area and take root or when seeds float into a suitable area and germinate. Spartina establishes itself on substrates（the base on which an organism lives） ranging from sand and silt to gravel and cobble and is tolerant of salinities ranging from that of near freshwater (0.05 percent) to that of salt water (3.5 percent). Spartina is particularly able to tolerate high salinities because salt glands on the surface of the leaves remove the salt from the plant sap. Because they lack oxygen, marsh sediments are high in sulfides that are toxic to most plants.
这一部分讲了几层，其中salinities解释了一下
In New Zealand the plant has spread rapidly, changing mudflats with marshy fringes to extensive salt meadows and reducing the number and kinds of birds and animals that use the marsh.
沼泽边缘的泥滩变成盐碱草地
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