Exoskeleton
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An exoskeleton is a skeleton that is on the exterior of an animal to both support the body shape and protect the internal organs, in contrast to an internal endoskeleton which is enclosed underneath other soft tissues. Some large, hard and non-flexible protective exoskeletons are known as shell or armour.
Discarded exoskeleton (exuviae) of dragonfly nymph
Exoskeleton of cicada attached to a Tridax procumbens (colloquially known as the tridax daisy)
Borings in exoskeletons can provide evidence of animal behaviour. In this case, boring sponges attacked this hard clam shell after the death of the clam, producing the trace fossil Entobia.
Animal
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Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, have myocytes and are able to move, can reproduce sexually, and grow from a hollow sphere of cells, the blastula, during embryonic development. Animals form a clade, meaning that they arose from a single common ancestor.
Sexual reproduction is nearly universal in animals, such as these dragonflies.
Predators, such as this ultramarine flycatcher (Ficedula superciliaris), feed on other animals.
Hydrothermal vent mussels and shrimps
The blue whale is the largest animal that has ever lived.