water activity
(Science: chemistry) An expression of the relative availability of water in a substance. Pure water has an water activity of 1.000. The water activity of a solution is one-hundredth its relative humidity.
Nutrients in the soil are essential to the proper growth of a land plant. This tutorial deals with the properties of soil and the factors (i.e. climate, parent material, local topography, vegetation, living organisms, and time) that brought soil to what it is today. ..
Lentic or still water communities can vary greatly in appearance -- from a small temporary puddle to a large lake. The size and depth of a still body of water are major factors in determining the characteristics of that ecosystem. Learn in this elaborate tutorial how life thrives in and influenced by a still-water habitat...
Leaves are the major photosynthetic organ of a plant. Apart from that, they are also crucial to water movement. In this tutorial, various plant processes are considered in more detail. It also includes topics on leaf arrangements, leaf types, leaf structure, leaf color, abscission, and importance to humans...
The gastrointestinal system breaks down particles of ingested food into molecular forms by enzymes through digestion and then transferred to the internal environment by absorption. Find out more about these processes carried out by the gastrointestinal system through this tutorial...
The circulatory system is key to the transport of vital biomolecules and nutrients throughout the body. Learn about the different components and functions of the human circulatory system dealt with in detail in this tutorial. The lymphatic system is also elucidated elaborately here...
Proteins have a crucial role in various biological activities. Get to know how proteins are able to perform as enzymes, cofactors, or regulators. In this tutorial, you will also know the common metabolic pathways of biomolecules, such as glucose and other carbohydrates, fats, proteins and amino acids, and essential nutrients...