Animals cells exchange oxygen and carbon dioxide with their surroundings by ____ across the outer coverings or membranes of cells.
During incomplete metamorphosis, an insect goes directly from an egg to a ______, which looks like a young adult insect without wings.
Animals with a nerve _____ have no specialized neurons.
____ are nerve cell with a unique structure for receiving and passing on information.
In a _____ circulatory system, blood always stays inside vessels and the heart.
_____ are tiny, thin-walled blood vessels where blood and body cells exchange substances.
A signal that causes an animal to react in some way is a ______.
A _____ is a place where two or more parts of a skeleton meet.
_____ respiration is the process in which cells use oxygen and digested food molecules to release the energy in food.
Some animals go through a period of major body changes called ____.
Animals that eat only other animals are ______.
A _____ is an organized grouping of neurons in the head of an animal with bilateral symmetry.
______ neurons are nerve cells that carry response information to muscles and other organs.
A hawk's long broad feathers provide _____, enabling it to fly very high or soar.
In ______ reproduction, one parent produces a new organism identical to itself.
The larva stage of a frog is called a _____.
The length of time between fertilization and birth is called the _____ period.
Sponges reproduce asexually by ______, or having offspring grow out of and break off from a parent.
Materials are exchanged between the embryo and the mother through an organ called the _______.
A ____ is an immature form of an animal that looks different from the parent.
With insects that undergo complete metamorphosis an egg hatches into a ______.