细菌已有 35 亿年的历史，也是地球上最古老的生物体之一。并对一系列疾病负有责任，包括霍乱、肺结核和瘟疫等。 但不是所有细菌都具有危险；在你的肠道中存在着数万亿种对健康至关重要的好菌。它们可以产生维生素、防止肿瘤的形成、帮助免疫系统对抗病原体和防止致癌物质等等。 请访问我们的网站 www.fuseschool.org，我们所有的视频都按主题和特定的顺序精心排列，并查看我们还提供了什么。评论、喜欢并与其他学习者分享。你可以提问，也可以回答问题，老师会回复你。 这些视频可用于翻转课堂模式或作为复习辅助工具。 点击这里查看更多视频：https://alugha.com/FuseSchool Twitter：https://twitter.com/fuseSchool 在 fuseSchool 平台和应用程序中获取更深层次的学习体验：www.fuseschool.org 此开放式教育资源在知识共享许可协议下免费使用：署名-非商业性 CC BY-NC（查看许可证契约：http://creativecommons.org/licenses/by-nc/4.0/）。你可以下载视频用于非营利性的教育用途。如果你想修改视频，请联系我们：info@fuseschool.org
Click here to see more videos: https://alugha.com/FuseSchool Learn the basics about particles in a metal, that are held together by metallic bonds. What are metallic bonds? Find out more in this video! This Open Educational Resource is free of charge, under a Creative Commons License: Attribution-
A surd is a square root which cannot be reduced to a whole number. Surds are irrational; they are decimals that never end and never repeat, so cannot be written as fractions. Leaving a number in it's surd form is easier and more accurate than writing and rounding the decimal places. We see surds
In this video we have a look at the similarities and differences between prokaryotic and eukaryotic cells. VISIT us at www.fuseschool.org, where all of our videos are carefully organised into topics and specific orders, and to see what else we have on offer. Comment, like and share with other lear
