Crypt
(Science: pathology) deep pit that protrudes down into the connective tissue surrounding the small intestine. The epithelium at the base of the crypt is the site of stem cell proliferation and the differentiated cells move upwards and are shed 3-5 days later at the tips of the villi.
Animals adapt to their environment in aspects of anatomy, physiology, and behavior. This tutorial will help you understa..
Plants need to regulate water in order to stay upright and structurally stable. Find out the different evolutionary adap..
The water cycle (also referred to as the hydrological cycle) is a system of continuous transfer of water from the air, s..
Adaptation, in biology and ecology, refers to the process or trait through which organisms or the populations in a habit..
Plantlife can be studied at a variety of levels, from the molecular, genetic and biochemical level through organelles, c..
This tutorial digs into the past to investigate the origins of life. The section is split into geological periods in the..