All organisms—from single-celled bacteria to multicellular animals—need to obtain and use energy. The Cells and Chemical Reactions Interactive E-book* takes a closer look at the process of metabolism in cells, including photosynthesis in plant cells and cellular respiration in plant and animal cells. Additionally, this e-book looks at how the rates of these reactions can be affected by temperature, pH, hydration levels, and enzymes.

Cells carry on the many functions needed to sustain life, including cell growth and development. The genetic information encoded in DNA molecules provides instructions for assembling protein molecules, which are both necessary for producing more cells and performing other cellular functions. The Cell Division and Differentiation Interactive E-book* explores these cellular processes for growth and development, including the selective expression of specific genes, which allow for the differentiation and specialization of cells.

The Cell Structure and Function Interactive E-book* explores how cells, the basic building blocks of all organisms, function as systems of organelles and associated structures in a dynamic equilibrium between their internal and external environments. The focus is on topics related to the structure of various types of cells, the molecular workings inside the cell, and the role of proteins as the main structural and functional molecules.

By asking questions, conducting investigations, and interpreting results, scientists now have a better understanding of what makes up the smallest unit of matter that has properties of an element. The Atomic Structure Interactive E-book* uses investigative evidence to examine the structure of atoms and the parts that make up atoms. Additionally, this e-book looks at the forces that hold an atom and an atom’s nucleus together, isotopes, radioactivity, nuclear fusion and fission, and the energy contained in atoms.

The Solar System Interactive E-book* explores what we know about our solar system’s planets, moons, and other celestial bodies. This e-book focuses on asteroids, comets, meteorites, and each of the eight planets in our solar system, including their moons and their rings. Solar system formation theories and technological advances used to study our solar system are also discussed.

The Universe Interactive E-book* explores how the organization of stars and galaxies comprise a universe and how research scientists use specialized instruments to collect data about stars and galaxies. This Enhanced E-book takes a closer look at our star, the Sun, and then uses this information to study the properties and characteristics of different types of stars. Following this exploration, the life cycle of stars, parallax, galaxies, and the organization of the universe are introduced.

Bacteria live in close association with humans. Bacteria are masters at exploiting a variety of niches in the human body. Most of these bacteria are harmless to the human body and many are important in assisting its normal, healthy functioning. Disease in humans results when organisms such as bacteria interfere with the normal operation of the human body. The Science of Food Safety Interactive E-book* explores this science underlying food safety.

Nutrition is an interdisciplinary subject. To maintain a healthy lifestyle, individuals need to make informed decisions about personal nutrition, taking into account information about cells, body systems, energy, matter, and molecules. The Nutrition Interactive E-book* provides an overview of nutrition and the other factors that contribute to making choices that lead to a healthy lifestyle. The focus is on the main types of nutrients and how much of each are needed to maintain a healthy body, depending on individual way of life.

The Nature of Light Interactive E-book* explains the characteristics of light, discusses the concept of light as waves, explores the idea of light and color, and ultimately answers the question, "What is light?" Topics covered include reflection and refraction, the electromagnetic spectrum, light perception, and emission spectra and absorption spectra. Teachers, students, and lovers of science will find the clear and concise format engaging and informative.

Interdependence of Life explores the interactions between organisms and the environments in which they live—Earth spheres, ecosystems, abiotic factors, biotic factors, populations characteristics, limiting factors, and carrying capacity—as well as species relationships. This Interactive E-book* examines, and demonstrates, the delicate balance that is kept by the organisms in these regions, not just from the perspective of the natural world, but based on human interactions and interference as well. The result is a representation of the rich tapestry of life that covers planet Earth.