Discovery of the Circulation of Blood NOS: Theories are regarded as uncertain; William Harvey overturned theories developed by the ancient Greek philosopher Galen on movement of blood in the body A...
Digestive System Diagram Human Digestive System The human digestive system includes the following: Glands?- the salivary glands, and glands in the pancreas that produce digestive juices The?stomach...
Methods of Absorption Digestion breaks down food into?smaller, soluble molecules These products of digestion then pass from the?lumen?of the intestine into the?blood They pass through the microvill...
Villi: Increasing the Surface Area The?ileum?(the second section of the small intestine) is adapted for?absorption It is?very long It has a?highly folded surface? It has?millions of villi?(singular...
Introduction to Digestion The digestive system is an example of an?organ system?in which several organs work together to digest and absorb food Digestion is a process in which relatively?large, ins...
Dichotomous Keys For anyone who doesn't specialise in studying a particular group of organisms, it can be very?difficult to identify, or ID, a species?when working in the field Correctly identifyin...
Cladistics & Reclassification The development of?DNA sequencing technology?means that classification can now be carried out on the basis of?evolutionary relationship Organisms classified in thi...
Clades The term?clade?can be defined as A group of organisms that have all descended from a common ancestor Cladistics?is the branch of science in which scientists put organisms into clades It invo...
Animal Phyla Features Animals are?multicellular,?eukaryotic?organisms They are?heterotrophs?and most have a?nervous system?that enables responses to the surrounding environment There are over?30 an...
受新冠疫情影響，SAT考試迎來重大改革！此前College Board宣布SAT將迎來機(jī)考時(shí)代。去年11月，大學(xué)理事會(huì)在美國(guó)及其它國(guó)家的一些國(guó)際學(xué)校試點(diǎn)舉行了SAT上機(jī)考試，80%的考生反映他們覺得機(jī)考比起筆考?jí)毫Ω。M織...
Plant Phyla Features All plants belong to the?plant kingdom Within the plant kingdom are several?phyla?(singular?phylum) Some plant phyla are small E.g. the Glaucophytes contain only 70 species and...
Examples of Classification Biological classification involves putting organisms into?groups, or?taxa?(singular?taxon) The taxa form a?hierarchy A?hierarchical system?is one in which?larger groups c...
