How can we help?
You can also find more resources in our
Select a category
Something is confusing
Something is broken
I have a suggestion
What is your email?
What is 1 + 3?
egg composed of shell and membranes that create a protected environment in which the embryo can develop out of the water
outermost membranous sac enclosing the embryo in higher vertebrates (reptiles, birds and mammals)
thin innermost membranous sac enclosing the developing embryo of higher vertebrates (reptiles, birds and mammals)
vascular fetal membrane that develops from the hindgut in embryonic higher vertebrates (reptiles, birds and mammals)
a simple water-soluble protein found in many animal tissues and liquids
a fibrous scleroprotein that occurs in the outer layer of the skin and in horny tissues such as hair feathers nails and hooves
tortoises and turtles
shell covering the back (of a turtle, tortoise, crab, etc.)
(zoology) the part of a turtle's shell forming its underside
crocodiles and alligators
vertical fracture plane
inactivity resulting from torpidity and lack of vigor or energy
solitary individuals come together to prevent heat loss
an elaborate and remarkable display on a lavish scale
Sense organ on snake's roof of mouth which detects airborne chemicals
A sensory organ between the eye and nostrils