题目原文:
Agnostids were a group of marine animals that became extinct about 450 million years ago. Agnostid fossils can be found in rocks in many areas around the world. From the fossil remains, we know that agnostids were primitive arthropods-relatives of modern-day insects. However, the fossil information does not allow paleontologists to determine with certainty what agnostids ate or how they behaved. There are several different theories about how agnostids may have lived.
Free-Swimming Predators
First, the agnostids may have been free-swimming predators that hunted smaller animals. It is known that other types of primitive arthropods were strong swimmers and active predators, so it is reasonable that the agnostids may have lived that way as well And while the agnostids were small, sometimes just six millimeters long, there were plenty of smaller organisms in the ancient ocean for them to prey on.
Seafloor Dwellers
Second, they may have dwelled on the seafloor. Again, there are examples of other types of primitive arthropods living this way, so it is possible that agnostids did too. On the seafloor they would have survived by scavenging dead organisms or by grazing on bacteria.
Parasites
Third, there is the possibility that the agnostids were parasites, living on and feeding off larger organisms. One reason that this seems possible is that there are many species of modern-day arthropods that exist as parasites, such as fleas, ticks, and mites. The agnostids might have lived on primitive fish or even on other, larger arthropods.
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学术写作:
Dr. Achebe: Outdoor education can have various benefits, such as connecting with nature and learning in a different environment. As part of an initiative to encourage more outdoor learning, there is a proposal to have teachers take students aged 5-18 outside of the classroom for outdoor classes once a month. In your response, please share your thoughts on whether outdoor classes once a month would be beneficial for students in this age group.
Kelly: We should avoid burdening teachers with additional responsibilities during instructional time. Teachers are already tasked with delivering quality education and managing classrooms effectively. Adding more duties, such as administrative tasks or non-teaching responsibilities, can divert their focus from teaching. Instead, we should prioritize supporting teachers in their primary role.
Andrew: Hands-on learning outside the classroom can help students understand environmental problems in a tangible way and spark their interest to learn more. For example, measuring air or water quality in local areas impacted by pollution can vividly demonstrate environmental threats. Outdoor learning experiences make environmental issues real to students, motivating them to care about finding solutions.
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