A primary source. That would be a source coming directly from someone who was in the war so you know it is reliable and probably the most accurate. A secondary source could be from a journalist or an outside mind that doesn't know the true experience of being in the war and is just observing from an outsiders view.
Actually the answer would happen to be : Scientists now gathered information and facts before creating a theory.
Answer: Muscle tone
Explanation: Muscle tone is actually a muscle tension. This tension (muscle tone) maintains the body in its position as it is, or in a particular desired position. Or, for example, during movement, when the body changes its position, these changes of position are regulated by muscle tone. When the body is at rest, some muscle tension exists, and depending on the general fitness of the body, that tension under the skin is more visible or less visible, that is, my muscles will be tighter or floppy.
<span>A negative reinforcer is a stimulus
that is removed and, thus, increases the probability of a response</span>
Reinforcement
aims to increase the response. Negative reinforcement is when a hostile stimulus
is removed in order to ensure that the chances of obtaining a response are high
