biology-dictionary_11-06-2009

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Malignant
Dangerous to health; characterized by progressive and uncontrolled growth (especially of a
tumor)
Malpighian tubule
A unique excretory organ of insects that empties into the digestive tract, removes
nitrogenous wastes from the blood, and functions in osmoregulation.
Mammalia
The vertebrate class of mammals, characterized by body hair and mammary glands that
produce milk to nourish the young.
Mammals
Any of various warm-blooded vertebrate animals of the class Mammalia, including humans,
characterized by a covering of hair on the skin and, in the female, milk-producing mammary
glands for nourishing the young.
Mammary glands
Milk – secreting organ of female mammals.
Mandible
The lower jaw of a vertebrate animal.
Mantle
A heavy fold of tissue in mollusks that drapes over the visceral mass and may secrete a shell.
Marginal
Forming a margin.
Marine
Living in salt water.
Marsupial
A mammal, such as a koala, kangaroo, or opossum, whose young complete their embryonic
development inside a maternal pouch called the marsupium.
Mass number
The sum of the number of protons and neutrons in an atom's nucleus.
Mast cell
A type of noncirculating white blood cell, found in connective tissue, that is the major
protagonist in allergic reactions; when an allergen binds to complementary antibodies on
the surface of a mast cell, large amounts of histamine are released from the cell.

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