As a part of a research, natasha initially had difficulty falling asleep in the sleep lab, but finally drifted into sleep and was not awakened when a student researcher knocked a can of soda off the desk. the electroencephalograph (eeg) is displaying theta waves with occasional sleep spindles. the researchers feel confident that natasha is:

Expalined

Explanation:

When electroencephalograph (EEG) is displaying theta waves with occasional sleep spindles, the  patient is in deep relaxation and in the second stage of sleep where there is a dominance of theta waves and occasional burst of sleep spindles. In this stage small distubances and sound does not break the sleep. In addition appearance of K- complexes is often associated with stage two sleep.

the fossil record provides evidence of a common ancestor to many species.

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.