[Free Registration/Login may be required to access all resource tools.] Centipedes and millipedes belong to the subphylum Myriapoda, which contains 13,000 species. They all live on land. They are divided among four classes: (1) Chilopoda...

A guide to support parents as they work with their students in comparison of length, weight, capacity, and numbers to 10.

Students will be able to sort pictures that are alike and determine which group has more and fewer pictures.

Practice adding and subtracting using the number line. Numbers used are 100 or less. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

[Free Registration/Login may be required to access all resource tools.] The process of molecules moving from an area where there are lots of molecules to an area where there are fewer molecules is known as diffusion. The diffusion of...

Pygmy sperm whales are usually seen in small groups of six or fewer individuals, but there are few documented sightings. They tend to stay in deep water, beyond the continental shelf, and not much is known about their behavior. Learn...

After World War Two, many women placed a higher priority on marriage and having a family. However, this trend changed during the 1950s and by 1960 more women were attending college, working outside of the home, marrying later, and having...

Basically, the stronger your immune system the healthier you are and, as a consequence, the more protected you are from environmental factors that lead to infection and sickness. If you eat foods that are rich in the nutrients your body...

A map from 1912 of the United States, subtitled "Distribution of Population and Railways in 1850." The map is color-coded to show population densities ranging from areas with fewer than 2 inhabitants per square mile to areas of 90 or...

A map from 1912 of the United States, subtitled "Distribution of Population and Railways in 1900" showing the increase in population and expansion of the railroad network since 1850. The map is color-coded to show population densities...