Are spiders related to crabs? Study the order of arthropods with a reading selection about animal diversity. It provides details about each class within the order, as well as vivid pictures and explanatory charts. 

Learn about viruses of humans and other animals, the Baltimore classification system, and the HIV life cycle.

Learn the system that scientists use to classify living things.

Detailed information about each of the five kingdoms. Each kingdom is separately described, but information is also summarized in a table.

This customizable digital textbook covers topics related to third-grade science. It is Next Generation Science Standards (NGSS) aligned.

Use the scientific reasoning and critical thinking to take an in-depth look at the basics of biology.

This resource contains general information about the class Mammalia and their unifying characteristics.