Is skin part of our innate immune system

All outer and inner surfaces of the human body a key part of the innate immune system. The closed surface of the skin and of all mucous membranes already forms a physical barrier against germs, which protects them from entering.

Bmust be the answer, as technically all organs move, so a is incorrect. all organs are made of different types of cells, so that isn’t a problem, so c is also incorrect. human hearts are very similar to many other animals’ hearts, so d is also incorrect, yet the heart is made of muscle, which is hard to grow in the lab so it would be correct to say b