Roman numerals are used to identify the charges on metal cations having multiple oxidation states. Five examples are provided for practice.

In this animated object, learners read an introduction to protein structure and function.

In this well-illustrated object, learners examine basic floral anatomy. The flower is the reproductive organ of the angiosperm.

Practice how to make research decisions using the 3 Rs.

Learners examine the periodic table to identify metallic elements that have either fixed or variable oxidation states.

Learners examine how the boiling point increases with increasing pressure. An example from industry is given.

In this animated lesson, students view the operation of an electromechanical relay. A brief quiz concludes the activity.

In this screencast, learners read about the parts of the eye.

In this interactive object, learners calculate the amount of heat evolved or absorbed in chemical reactions. Four practice problems are provided.

In this interactive object, learners read about the occupations that are most at risk for bloodborne pathogen exposure. They also read about the most common pathogens and how they are transmitted. This learning object is based on information from the U.S. Occupational Safety and Health Administration.

In this well-illustrated object, learners examine the structures and properties of the four types of solids: molecular, metallic, ionic, and covalent network. Five interactive questions are provided.

In this interactive object, learners examine the structure and function of the sense of taste.

In this animated object, learners examine neutral fats, phospholipids, and cholesterol. The molecular formula and general function for each are shown.

Learners examine phase diagrams that show the phases of solid, liquid, and gas as well as the triple point and critical point.

Learners use the coefficients in a balanced equation to develop the mole ratios of reactants and products involved in the reaction. Five interactive examples illustrate the method, and students test their knowledge by working four problems.

In this animated object, learners examine the various connective tissue layers of the muscle organ. The terms "prime mover," "synergist," "antagonist," "origin," and "insertion" are defined.

In this animated object, learners examine the formation of ester bonds in the synthesis of lipids using triglyceride biosynthesis as an example. Ester bond formation is described as a dehydration synthesis reaction.

In this animated object, learners examine the eight cranial bones, the fourteen facial bones, and the ribs.

Students identify the various regions of the human body through drag-and-drop exercises.

In this animated object, learners examine the mechanisms for gas exchange among the lungs, blood, and tissues.