I think the circulatory system is the best body system because we need the heart to stay alive, many people live with only one lung. but we need the respiratory system to let oxygen in, and let carbon dioxide out.
<span>The cytoskeleton helps the cell maintain
its shape and is involved in many forms of cell movement. It is also
involved in moving organelles within the cell.</span>
Steroid hormones are nonpolar and cross the cells plasma membrane , binding to receptors inside the cell. ... It allows for the movement of ions across the plasma membrane
Answer:
"heart attacks are most often caused by a sudden drop in blood pressure."
