Its B. 13- i just took the test and i got it right.
Nice question of yours..............
1. Circulatory system = the parts of the body that are related to the movement of blood
2. Internal system = the organs inside the body and how they function together
3. Muscular System = the part of the body that is made up of the muscles
4. Skeletal system = The bones found in the body
A measure of tactile acuity defined as the smallest separation at which two points applied simultaneously to the skin can be clearly distinguished from a single point. It varies from 1 or 2 millimetres in the finger pads and tongue to more than 60 millimetres on the upper arm, upper thigh, and back.
