4. Which of the following statements are accurate?
A. The heartbeat in a human heart is initiated by the atrioventricular mode.
B. During systole, the heart's ventricle(s) is/are relaxing and filling with blood.
C. During systole, blood will be pumped from the heart into the veins of the body
D. The pulse is used to determine one's heart rate.
E. The nervous system and certain hormones can alter pacemaker activity.

Astudent sees several ants walking up a wall following the exact same trail that an ant took earlier. she wants to apply the scientific method to determine how the ants detected the trail. which of these steps would come first in her application of the scientific method? perform an experiment by cleaning the scent away from part of the trail. draw a conclusion that the ants follow a scent trail. make a prediction about what the ants will do after she cleans away part of the trail. hypothesize that the ants are following a scent trail that the first ant left.