Cycle in the female reproductive system that prepares it for reproduction.

Study of the form, shape, and appearance of an animal

Osteichthyes class of vertebrates

Structures in the mammary systems that use nutrients from the blood to make milk

Hard outer covering that protects and supports the body, and keep internal organs from being injured

Flexible material at the end of bones.

Proportion of the animal's body features in relation to one another or to the whole body of an ideal breed or species.

The liquid in the circulatory system

An aquatic animal with an exoskeleton

An animal kept as a pet

Hard part of the skeleton

Animal with one compartment stomach.

Period of time in mammals where the female carries a developing embryo in her uterus.

Muscle automatically controlled by the lower part of the brain

Invertebrate animal with a soft body and a hard shell for protection

Vertebrate that reproduces by mating male and female of the same species.

Exchange of gases in the lungs between the blood and the atmosphere

The production of milk.

An unborn animal during the second half of pregnancy.

Study of form, structure, and configuration of an organism.

An animal without a backbone

Exchange of gases in the lungs between the cells and the blood within the body

Milk producing glands by which newborn mammals are fed