With each heartbeat, the muscle cells coordinate themselves so that each contraction is forceful enough to circulate blood through the entire body. the beat begins in the node, which sets the tempo of each beat, thus giving it the name of pacemaker. sinoatrial pericardium atrioventricular electrocardiogram semilunar

did you fail the test? xd

i believe it's c. the trait for large beaks will be passed on to future generations through natural selection.

since eventually smaller beaks would have to find another source of food or even eventually just die out from the lack of food.

the alkaline earth metals (beryllium (be), magnesium (mg), calcium (ca), strontium (sr), barium (ba), and radium (ra)) are a group of chemical elements in the s-block of the periodic table with very similar properties: shiny. silvery-white. hopefully this ? i didn't fully understand the question

the correct answers are;

a. the rock was made from more than one type of material.

e. layers of hot liquids in the rock cooled and solidified at different temperatures.

these are the two options that are related to the statement given above.