Module 6 课时达标训练(二十四)
Ⅰ.阅读理解
Living in the wild can be hard. Finding food and staying safe aren't easy. Each day, animals struggle to sur-vive in their habitats. Not all animals get by on their own. Some animals form a close partnership with other kinds of animals. These pairings are called symbiotic (共生的) relationships.
In a symbiotic relationship, the animals depend on each other. One animal helps the other meet its needs. Sounds good, right? Not always. Some animals are not very kind to their partners. In some cases, one animal meets its needs but hurts its partner. Take ticks (壁虱) for example. These insects suck blood to live. To get blood, they attach themselves to other kinds of animals. Ticks can pass germs that cause disease instead of helping their hosts.
In other relationships, animals don't treat their part-ners so poorly. Both animals benefit, or get help, from living with the other animal.
