[Free Registration/Login may be required to access all resource tools.] Sponges are classified in the phylum Porifera, from the Latin words meaning "having pores." Sponges are sessile, meaning they cannot move, so they filter water...

[Free Registration/Login may be required to access all resource tools.] Turtles are reptiles in the order Testudines. Most turtle bodies are covered by a special shell developed from their ribs. About 300 species are alive today, and...

[Free Registration/Login may be required to access all resource tools.] Explains inertia and how it affects motion, the relationship between inertia and mass, and how to overcome inertia.

[Free Registration/Login may be required to access all resource tools.] How a mirror forms images and how to distinguish between real and virtual images, and the different types of mirrors and the images they produce.

[Free Registration/Login may be required to access all resource tools.] Properties of solid matter and comparison of different types of solids.

[Free Registration/Login may be required to access all resource tools.] Diabetes is a non-infectious disease in which the body is unable to control the amount of sugar in the blood. People with diabetes have high blood sugar, either...

[Free Registration/Login may be required to access all resource tools.] Regular physical exercise is important in preventing lifestyle diseases such as cardiovascular disease, some types of cancer, type 2 diabetes, and obesity. Regular...

[Free Registration/Login may be required to access all resource tools.] A pedigree is a chart that shows the inheritance of a trait over several generations. A pedigree is commonly created for families, and it outlines the inheritance...

[Free Registration/Login may be required to access all resource tools.] Plants may not be able to move, but they are able to change how they grow in response to their environment. Growth toward or away from a stimulus is known as a...

[Free Registration/Login may be required to access all resource tools.] Definition of alloys and examples.

[Free Registration/Login may be required to access all resource tools.] Definition of buoyant force and how weight and density relate to buoyant force and the ability to float.

[Free Registration/Login may be required to access all resource tools.] Explains what distance is, its SI unit, and how to use maps to measure distance.

[Free Registration/Login may be required to access all resource tools.] Properties of matter in the plasma state and where plasma is found.

[Free Registration/Login may be required to access all resource tools.] Protons and how they relate to elements, and what protons are made of.

[Free Registration/Login may be required to access all resource tools.] What a machine is, the three ways that machines make work easier and simple and compound machines.

[Free Registration/Login may be required to access all resource tools.] Difference between velocity and speed, using vector arrows to represent velocity, objects that have different velocities and how to calculate average velocity.

[Free Registration/Login may be required to access all resource tools.] When is a person considered an adult? That depends. Most teens become physically mature by the age of 16 or so. But they are not adults in a legal sense until they...

[Free Registration/Login may be required to access all resource tools.] Arachnids are a class of joint-legged invertebrates in the subphylum Chelicerata. They live mainly on land but are also found in freshwater and in all marine...

[Free Registration/Login may be required to access all resource tools.] There are almost 27,000 species of bony fish, which are divided into two classes: ray-finned fish and lobe-finned fish. Most bony fish are ray-finned. These thin...

[Free Registration/Login may be required to access all resource tools.] Did you know that fish, amphibians, reptiles, birds, and mammals are all related? They are all chordates. Chordates are a group of animals that includes vertebrates,...

[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...

[Free Registration/Login may be required to access all resource tools.] The word "worm" is not very scientific. But it is a word that informally describes animals (usually invertebrates) that have long bodies with no arms or legs. Worms...

[Free Registration/Login may be required to access all resource tools.] When a baby girl is born, her ovaries contain all of the eggs they will ever produce. But these eggs are not fully developed. They develop only after she starts...

[Free Registration/Login may be required to access all resource tools.] Breathing is only part of the process of bringing oxygen to where it is needed in the body. After oxygen enters the lungs, what happens? Learn more about processes...