Khan Academy
Khan Academy: Frog Development Examples
How do you build a frog from a single cell? Learn how body axes are established and nerve tissue is induced in frog embryos.
Agnes Scott College
Agnes Scott College: Sofia Kovalevskaya (1850 1891)
This site provides a biography of the mathematician, writer, and advocate of women's rights, Sofia Kovalevskaya (1850-1891 CE).