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Some of these glands are specialized as mammary glands, producing milk to feed the young.Mammals breathe with lungs and have a muscular diaphragm separating the thorax from the abdomen which helps them draw air into the lungs.Anatomy is the branch of biology concerned with the study of the structure of organisms and their parts.
The history of anatomy is characterized by a progressive understanding of the functions of the organs and structures of the human body.
Cardiac muscle is found only in the heart, allowing it to contract and pump blood round the body.
Sharks and rays are basal fish with numerous primitive anatomical features similar to those of ancient fish, including skeletons composed of cartilage.
They have a bony skeleton, are generally laterally flattened, have five pairs of gills protected by an operculum, and a mouth at or near the tip of the snout. Bony fish have a swim bladder which helps them maintain a constant depth in the water column, but not a cloaca.
They mostly spawn a large number of small eggs with little yolk which they broadcast into the water column Mammals are a diverse class of animals, mostly terrestrial but some are aquatic and others have evolved flapping or gliding flight.