Evidence of a living thing that lived long ago is called a(n) _____________.
By observing the patterns of dinosaur ______________, scientists learned how the dinosaurs walked.
Most fossils are found in _______________.
When an organism dies, its _______________ quickly decay or are eaten.
The hard parts of dead organisms are more likely to become a ____________ fossil.
Tree sap can harden into ____________ and preserve an entire organism.
Some fossils form when an organism presses into a soft surface, leaving a(n) ___________.
When an entire group of organisms die, it is probably because they did not adapt to ____________.
If an organism does not meet its needs after a change, it can slowly __________.
Scientist _____________ living things according to how many of their kind are left.
If only a few of its kind are left, the species is ______________.
When no members are left, the species is _______________.
Scientists try to keep animals from becoming endangered or ____________ by moving the animals to places where they are safe and protected.
Scientists try to keep animals from becoming endangered or extinct by moving the animals to places where they are __________.