Two items of the same kind.
Dictionary > Couplet
You will also like...

Genetic Engineering Advantages & Disadvantages
This tutorial presents the benefits and the possible adverse eventualities of genetic engineering. Know more about this ..

DNA Structure & DNA Replication
DNA is a double helix structure comprised of nucleotides. A nucleotide, in turn, is made up of phosphate molecule, deoxy..

Photosynthesis – Photolysis and Carbon Fixation
Photosynthesis is the process that plants undertake to create organic materials from carbon dioxide and water, with the ..

Human Biology – Food and Digestion
This tutorial recognizes the importance of food as a source of energy that will fuel many biological processes. A good d..

Roots
This study guide tackles plant roots in greater detail. It delves into the development of plant roots, the root structur..

Early Mammals on Earth
The Earth's ecosphere was rapidly changing and throwing up a wide range of ecological niches that new adaptive organisms..