astronaut: Someone trained to travel into space for research and exploration.
calcium: A chemical element and alkali metal common in minerals of the Earth’s crust and in sea salt. It is also found in bone mineral and teeth, and can play a role in the movement of certain substances into and out of cells.
chitin: A tough, semi-transparent substance that is the main component of the exoskeletons of arthropods (such as insects). A carbohydrate, chitin also is found in the cell walls of some fungi and algae.
crustaceans: Hard-shelled water-dwelling animals including lobsters, crabs and shrimp.
exoskeleton: A hard, protective outer body covering of many animals that lack a true skeleton, such as an insect, crustacean or mollusk. The exoskeletons of insects and crustaceans are largely made of chitin.
insect: A type of arthropod that as an adult will have six segmented legs and three body parts: a head, thorax and abdomen. There are hundreds of thousands of insects, which include bees, beetles, flies and moths.
invertebrate: An animal lacking a backbone. About 90 percent of animal species are invertebrates.
ligament: A fibrous and elastic material that connects one bone to another.
mineral: Crystal-forming substances that make up rock, such as quartz, apatite or various carbonates. Most rocks contain several different minerals mish-mashed together. A mineral usually is solid and stable at room temperatures and has a specific formula, or recipe (with atoms occurring in certain proportions) and a specific crystalline structure (meaning that its atoms are organized in regular three-dimensional patterns).
moon: The natural satellite of any planet.
polymer: A substance made from long chains of repeating groups of atoms. Manufactured polymers include nylon, polyvinyl chloride (better known as PVC) and many types of plastics. Natural polymers include rubber, silk and cellulose (found in plants and used to make paper, for example).
predator: (adjective: predatory) A creature that preys on other animals for most or all of its food.
salt: A compound made by combining an acid with a base (in a reaction that also creates water). The ocean contains many different salts — collectively called “sea salt.” Common table salt is a made of sodium and chlorine.
shell: The normally hard, protective outer covering of something. It could cover a mollusk or crustacean (such as a mussel or crab), a bird’s egg or some other relatively soft tissue that needs protection (such as a tree nut or peanut). (in munitions) An explosive bullet, bomb, grenade or other projectile.
technology: The application of scientific knowledge for practical purposes, especially in industry — or the devices, processes and systems that result from those efforts.
tendon: A tissue in the body that connects muscle and bone.
tool: An object that a person or other animal makes or obtains and then uses to carry out some purpose such as reaching food, defending itself or grooming.
