preserved: to keep something as it is, especially in order to prevent it from decaying or being damaged or destroyed
part of speech: verb. Putting varnish on wood is a way of preserving it.
fossil: the shape of a bone, a shell, or a plant or animal that has been preserved in rock for a very long period
part of speech: noun. The teacher is showing a fossil.
cast: an object made by pouring hot liquid into a container and leaving it to become solid
part of speech: noun. This fossil is made of cast
amber: a hard, transparent, yellowish-brown substance that was formed in ancient times from resin (= a substance produced by trees) and is used in jewellery
part of speech: noun. He has a collection of prehistoric insects preserved in amber
fish: an animal that lives in water, is covered with scales, and breathes by taking water in through its mouth, or the flesh of these animals eaten as food
part of speech: noun. Several large fish live in the pond.
mineral: a valuable or useful chemical substance that is formed naturally in the ground
part of speech: noun. I learn the value of this mineral at class.
tar: a black substance, sticky when hot, used especially for making roads
part of speech: noun. Be careful with the tar.
crab: a sea creature with five pairs of legs and a round, flat body covered by a shell, or its flesh eaten as food
part of speech: noun. We walked along the beach collecting small crabs.
mud: earth that has been mixed with water
part of speech: noun. The vehicles got bogged down in the heavy mud
trace: to find someone or something that was lost
part of speech: verb. The police are trying to trace the mother of a newborn baby found abandoned outside a hospital.
sponge: a soft substance that is full of small holes and can absorb a lot of liquid, and is used for washing and cleaning
part of speech: noun. I buy a sponge at the supermaket
impression: a mark made on the surface of something by pressing an object into it
part of speech: noun. The bookcase had left an impression in the rug.
sediment: a soft substance that is like a wet powder and consists of very small pieces of a solid material that have fallen to the bottom of a liquid
part of speech: noun. There was a brown sediment in the bottom of the bottle.
mold: a soft green, gray, or black growth that develops on old food or on objects that have been left too long in warm, slightly wet places
part of speech: noun. Look there is mold on the bread.
footprint: the mark made by a person's or animal's foot
part of speech: noun. I left my footprint there.
carbon: a chemical element that exists in its pure form as diamond or graphite, and is an important part of other substances such as coal and oil, as well as being contained in all plants and animals
part of speech: noun. They used carbon dating tests to authenticate the claim that the skeleton was 2 million years old.
horseshoe: a U-shaped piece of metal that is attached to the bottom of a horse's hoof to protect it
part of speech: noun. For many people the horseshoe is a symbol of good luck.
trilobite: a simple, flat sea creature that lived in the earliest period of life on earth, with a hard outer layer and a body in three parts
part of speech: noun. Though commonly observed, blindness in trilobites remains difficult to explain in terms of adaptation.
dinosaur: a type of reptile that became extinct about 65,000,000 years ago. There were many different types of dinosaur, some of which were extremely large.
part of speech: noun. I like to go to the museum, I learn a lot of dinosaur.