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animal that eats only plants or parts of plants


animal that eats other animals or the remains of other animals


animal that eats plants and animals or animal flesh


animal with a backbone


animal without a backbone

radial symmetry

body parts arranged in a circle around a central point

bilateral symmetry

body parts arranged in a similar way on both sides of the body, with each half being nearly a mirror image of the other half


thick, hard, outer covering that protects and supports arthropod bodies and provides places for muscles to attached


animal that has a notochord, a nerve cord, pharyngeal pouches and a postanal tail present at some stage of development


firm but flexible structure that extends along the upper part of the chordates body

nerve cord

tubelike structure above the notochord that in most chordates develops into the brain and spinal cord


supportive framework of bone and/or cartilage that provides an internal place for muscle attachment and protects a vertebrate's internal organs


tough, flexible tissue that joins vertebrae and makes up all or part of the vertebrate endoskeleton


backbones that are joined by flexible cartilage and protect a vertebrate's spinal nerve cord


vertebrate animal whose internal temperature changes when the temperature of its environment changes


vertebrate animal with a nearly constant internal temperature


inactivity in cold weather; cyclic response of inactivity and slowed metabolism that occurs during periods of cold temperatures and limited food supplies


inactivity in hot, dry months

amniotic egg

egg covered with a shell that provides a complete environment for the embryo's development; for reptiles, a major adaptation for living on land

contour feather

strong, lightweight feather that give birds their coloring and shape and that are used for flight

down feathers

soft, fluffy feathers that provide an insulating layer next to the skin of adult birds and that cover the bodies of young birds


vertebrate animals with a nearly constant internal temperature


endothermic vertebrates that have hair, teeth specialized for eating certain foods, and mammary gland, in females, mammary glands produce milk for feeding their young

mammary glands

glands of mammals in females, produce milk to feed their young


a mammal that lays eggs with tough, leathery shell and whose mammary glands do not have nipples


a mammal with an external pouch for the development of its immature young


a mammal whose offspring develop inside a female uterus

gestation period

period during which an embryo develops in the uterus, the length of times varies among species


an organ that develops from tissues of the embryo and tissues that line the inside of the uterus and that absorbs oxygen and food from the mother's blood

umbilical cord

connects the embryo to the placenta; moves food and oxygen from the placenta to the embryo and removes the embryo's waste products

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