Anatomy of a Wave
A wave is described by its wavelength (or the distance between two sequential crests or two sequential troughs), the wave period (or the time it takes a wave to travel the wavelength), and the wave frequency (the number of wave crests that pass by a fixed location in a given amount of time
Oxygen and carbon dioxide travels to and from tiny air sacs in the lungs, through the walls of the capillaries, into the blood. Blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs.

The thalamus is a bundle of about twelve nuclei in which every sense except smell has a synapse; it is the "gateway" to the cerebral cortex. The correct answer to blank above is "is a bundle of about twelve nuclei in which every sense except smell has a synapse; it is the "gateway" to the cerebral cortex".
Circulation is your blood flow, well in my words. Like for example "I'm losing circulation in my arm." They are having their blood flow slow down or even stopped. It doesn't always have to be blood, it can be any fluid