Answer:
I'm pretty sure its Skeletal System
Explanation:
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
Your immune system uses a huge army of defender cells - different types of white blood cell. You make about 1000 million of them every day in your bone marrow. Some of these cells, called macrophages, constantly patrol your body, destroying germs as soon as they enter. This is your 'natural' or inborn immunity. But if an infection begins to take hold, your body fights back with an even more powerful defence of T- and B-cells. They give you acquired immunity, so that the same germ can never make you as ill again.
