This is what covers birds' skin.

This word describes something that does not absorb water, including birds' feathers.

This word describes an animal's ability to maintain a constant body temperature.

This is the name of the well-developed part of mammals' brains that allows them to have complex thoughts.

This is the name of the sharp teeth that allow carnivores to tear apart their meat.

This term describes that sperm fertilize a bird's egg inside the female bird by sexual reproduction, rather than fertilization in the nest (after the eggs are laid).

This term describes something with a shape that reduces air drag, such as a wing.

This is the number of chambers birds and mammals' hearts have.

This is the name of the muscle that helps move air in and out of mammals' lungs so that they can breathe.

This is the name of the group of cells in the skin that produce water when the animal is too hot. When the water evaporates, the animal's temperature drops.

This is the UNFERTILIZED product of birds' reproductive cycles that humans eat.

This is the location of the largest and strongest muscles in a bird (which allow it to fly).

This is the term that describes animals that have a spinal column.

This is the name of the glands that make milk for mammals to feed their babies.

This is the name for the teeth in the back of a mammal's mouth that allow it to grind its food.

This is where bird embryos develop.

This is the name of the fluffy feathers underneath the larger, outer ones that help with insulation. We put them in our pillows and blankets.

This is the kingdom that birds and mammals belong to.

This is the NUMBER of tiny bones (ossicles) in the ear that move with the eardrum, allowing mammals to hear.

This is what covers mammals' skin and can help them stay warm.

This is the name of the hard/pointed part of birds' mouths.

This is one way that birds are lightweight so they can fly (4 possibilities).

This term describes birds and mammals that eat only plant material (not meat).

This word describes the type of leg/foot arrangement and angle that humans, bears, rabbits, raccoons, red pandas, skunks, and kangaroos have.

This is the name of the part that connects a mammal's fetus to its mother's uterus. Some animals eat it after giving birth because it has a lot of nutrients.