If the connection between the sa node and av node becomes blocked,
a) the ventricles will beat faster.
b) the ventricles will beat independently of the atria.
c) the ventricular rate of contraction will not be affected.
d) the stroke volume will increase.
e) tachycardia will occur.

what's the rest of the question

answer: 21

step-by-step explanation:

divide 630 by 30. 30 goes into 630 21 times

idk

explanation:

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