Which of the following body systems has a main function of sending signals form one part of the body to other parts of the body

Astudent observes a star from two positions of earth in its orbit, in summer and winter, and measures the change in the position of the star. which of these can be best calculated by this method?

Students in biology are studying the macromolecules of life. they used a calorimeter to determine the calories in various types of food. once the lab was completed, the students ate the left over food samples. monica commented that in just 6 or 7 "chews" of the saltine, it was gone; nothing but a sticky paste in her mouth. elaborate on what happened chemically while chewing the saltine. include the macromolecules present.

Apatient has an open displaced fracture of the second cervical vertebra. this is her fifth visit and the fracture is healing normally. what icd-10-cm code is reported?