1. Contraction
2. Actin
3. Tendons
4. Epidermis
5. Dermis
6. Acne
7. A nerve signal from the brain arrives at the intersection of the nerve and muscle cells and releases acetylcholine from the neuron. This triggers chemical changes in the muscle cell involving ions, including Ca2+. Calcium triggers the thick filaments, made of myosin, to attach to the thin filaments, made of actin, in the muscle cell, and the myosin pulls the actin toward the center of the muscle cell. ATP causes the release of the actin fibers, allowing the muscle to relax and the process to begin again.
For Penn Foster.
What kind of cell theres different kinds i mean a lot of different kinds
Plant cells? Sex Cells? Blood Cells? White Blood Cells?
There are several reasons why the use of alternative sources of energy would be beneficial to the Earth and its people, but the main reason is that fossil fuels will run out soon.
B) One swims freely and the other often lives attached to a hard surface.
The control group is B and experimental group is A
