Answer:
When people lift weights, microscopic damage (microtears) occurs to the myofibrils within the muscle fiber. These microtears stimulate the body's repair response. ... The increased number of myofibrils causes muscle fibers to enlarge, increasing their volume and size.
Explanation:
Each cell expresses, or turns on, only a fraction of its genes. The rest of the genes are repressed, or turned off.
The turned on genes are then first transcribed into messenger RNA by the process of Transcription.
Then the mRNA is Translated into protein by the process called Translation.
This is how the specific genes are expressed.
<span>Receptors in muscles provide the brain with information about body position and movement. The brain controls the contraction of skeletal muscle. The nervoussystem regulates the speed at which food moves through the digestive tract.</span>
