Final answer:
The average stroke volume (SV) for a normal resting heart is 70 mL/beat, aligning with option A. The SV, affected by various physiological variables, falls within a normal range of 55-100 mL for most individuals.
Step-by-step explanation:
The stroke volume (SV) for a normal resting heart is typically measured in milliliters per heartbeat and indicates the amount of blood pumped by the left ventricle in one contraction. According to the provided information, a mean SV for a resting 70-kg individual would be approximately 70 mL. It is important to note that the normal range for SV can vary from 55-100 mL, and is influenced by several factors including the size of the heart, physical and mental condition, sex, contractility, duration of contraction, preload or end-diastolic volume (EDV), and afterload or resistance. During the ventricular ejection phase, the pressure within the ventricle is greater than the pressures in the pulmonary trunk and the aorta, leading to the ejection of blood and determining the SV.
In conclusion, for the given multiple-choice question, the correct option is A) 70 mL/beat, which is the average SV for a resting individual.