[Free Registration/Login may be required to access all resource tools.] Using latitude and longitude to find a location.

[Free Registration/Login may be required to access all resource tools.] How valuable minerals and metals are mined.

[Free Registration/Login may be required to access all resource tools.] Foods such as whole grain breads, fresh fruits, and fish provide nutrients you need for good health. But different foods give you different types of nutrients. You...

[Free Registration/Login may be required to access all resource tools.] Frogs and toads are amphibians in the order Anura. In terms of classification, there is actually not a big difference between frogs and toads. Learn more about frogs...

[Free Registration/Login may be required to access all resource tools.] How important is your skeleton? Can you imagine your body without it? You would be a wobbly pile of muscle and internal organs, and you would not be able to move....

[Free Registration/Login may be required to access all resource tools.] The menstrual cycle is a series of changes in the reproductive system of mature females that repeats every month. Learn more about the menstrual cycle in this...

[Free Registration/Login may be required to access all resource tools.] Recombinant DNA is the combination of DNA from two different sources. For example, it is possible to place a human gene into bacterial DNA. Recombinant DNA...

[Free Registration/Login may be required to access all resource tools.] When you think of worms, you probably picture earthworms. There are actually many types of worms, including flatworms, roundworms, and segmented worms. Earthworms...

[Free Registration/Login may be required to access all resource tools.] Definitions of atomic number and mass number.

[Free Registration/Login may be required to access all resource tools.] Definition of a chemical bond, why they form and the different types.

[Free Registration/Login may be required to access all resource tools.] Definition of chemical reaction rate and factors that influence it.

[Free Registration/Login may be required to access all resource tools.] Introduction to forms of energy including the seven different forms.

[Free Registration/Login may be required to access all resource tools.] Explores the function of a heating system and how it works.

[Free Registration/Login may be required to access all resource tools.] Explains hydrogen bonds including why they form and changes of state.

[Free Registration/Login may be required to access all resource tools.] International System of Units (SI) and converting units.

[Free Registration/Login may be required to access all resource tools.] Metallic bonds and how they influence the properties of metals.

[Free Registration/Login may be required to access all resource tools.] What a transverse wave is, its crests and troughs and what an S wave is.

[Free Registration/Login may be required to access all resource tools.] The lymphatic system is a network of vessels and tissues that carry a clear fluid called lymph. The lymphatic system works with the cardiovascular system to return...

[Free Registration/Login may be required to access all resource tools.] You might have noticed that sometimes your urine is darker than usual. This can happens when your body is low on water and trying to reduce the amount of water lost...

[Free Registration/Login may be required to access all resource tools.] Nutrients in the foods you eat are needed by the cells of your body. How do the nutrients in foods get to your body cells? What organs and processes break down the...

[Free Registration/Login may be required to access all resource tools.] Just about all human behaviors are learned. Learned behavior is behavior that occurs only after experience or practice. Learned behavior has an advantage over innate...

[Free Registration/Login may be required to access all resource tools.] What is a mammal? They walk, run, swim, and fly. They live in the ocean, fly in the sky, walk on the prairies, and run in the savanna. There is a tremendous amount...

[Free Registration/Login may be required to access all resource tools.] Another exception to Mendel's rules is polygenic inheritance, which occurs when a trait is controlled by more than one gene. This means that each dominant allele...

[Free Registration/Login may be required to access all resource tools.] The first archaea described could survive in extremely harsh environments in which no other organisms could survive. As a result, archaea are often distinguished by...