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.
Thomas Hunt Morgan, who studied fruit flies, provided the first strong confirmation of the chromosome theory. Morgan discovered a mutation that affected fly eye color. ... Based on the inheritance pattern, Morgan concluded that the eye color gene must be located on the X chromosome.
The density would be 14.567 lb/cu ft
Mitochondria is the powerhouse of the cell
Hope this helped
