Biology 2e is designed to cover the scope and sequence requirements of a typical two-semester biology course for science majors. The text provides comprehensive coverage of foundational research and core biology concepts through an evolutionary lens. Biology includes rich features that engage students in scientific inquiry, highlight careers in the biological sciences, and offer everyday applications. The book also includes various types of practice and homework questions that help students understand—and apply—key concepts. The 2nd edition has been revised to incorporate clearer, more current, and more dynamic explanations, while maintaining the same organization as the first edition. Art and illustrations have been substantially improved, and the textbook features additional assessments and related resources.

By the end of this section, you will be able to do the following:

Describe hypersensitivity
Define autoimmunity

This one-page study guide on immune system diseases covers key terminology and describes some common immunity disorders. It is available for download with free registration.

A free CK-12 account is required to view all materials.

"There are many different people in the world, and each one is special. However, some people may have physical or mental challenges that require extra help or assistance."

Whether it is caused by a certain type of soap or chemical, or a certain plant, rashes aren't any fun. Read more about certain types of rashes, what to expect when you have a rash, and how to avoid getting them.

This page for the huge KidsHealth site gives you a jumping-off point and an overview of the site's content, purpose, and usage. With sections for parents, kids, and teens, KidsHealth has been online since 1995 and today it is accessed 250,000 times on an average weekday. The Kids area features thousands of topics in sections like Staying Healthy, Growing Up, Everyday Illnesses & Injuries, and Dealing with Feelings. There are games, interactive features, and a glossary of medical terms. Teen topics include School & Jobs, Staying Safe, and Food & Fitness. This is a great place for doctor-approved health information. Available in English and Spanish.

Learn about some autoimmune disorders that affect human health.

A free CK-12 account is required to view all materials.

Identify places in a typical room where "creepy crawlies" like dust mites, ants, lice and silverfish might live. Then check out places on the human body that dust mites may inhabit, and learn about the disease and other problems dust mites can cause.

WebMD's Allergies Health Center is your one-stop place for information on allergies. Contains news articles, fact sheets, tips for beating allergies, plus more.