Which of these never changes during a chemical change?
a. the arranhement of the atoms
b. the total number of molecules
c. the total number of atoms
d. the color of the reactants

And give a detailed description! scientist observes the boundary between two tectonic plates for a decade and finds that no new volcanoes have formed over the course of her investigation. does this result support the theory of plate tectonics? why or why not?

Acell in the human nervous system whose primary function is to form myelin and the blood-brain barrier, respond to injury, remove debris, and enhance learning and memory is called a(n) cell.

Need the diagram below, which is not drawn to scale, shows the position of the earth, moon, and sun. what type of eclipse occurs when the earth, moon, and sun are lined up in the order shown? a. planetary eclipse b. solar eclipse c. martian eclipse d. lunar eclipse