True or false: The axon of a neuron can only communicate with other neuronal cells.

Which of the following structures is also called the windpipe?

Leukocytes (white blood cells) account for about ________ of the cells in human blood.

The most efficient lungs with respect to oxygen uptake are found in this group of vertebrates.

Connective tissue includes adipose tissue, tendons, bone, cartilage, and blood. What do all these tissues have in common?

The ____________ valve guards the opening between the left atrium and left ventricle.

Why doesn’t the stomach acid just digest right through the wall of the stomach?

Saliva contains the hydrolytic enzyme, salivary amylase, which initiates the breakdown of the polysaccharide ________ into the disaccharide, maltose.

The liquid portion of blood that contains metabolites, wastes, hormones, ions, and a variety of proteins is called the ________.

Describe the electrical components of the heart and their role in regulating contraction and relaxation of cardiac muscle.