What system tells the muscular system which muscles to contract and when to contract

b. read the phase at the intersection of any given temperature and pressure.

condenser is used to focus in the light microscope.

the earth is thought to have been formed about 4.6 billion years ago by collisions from a cloud of hydrogen, helium, rock, ice and other materials. these were pulled together by gravity to form objects in and around earth like- asteroids and small early planets called planetesimals.

so, the best possible answer to this question will be option d- to harden materials to form different parts of earth’s layers