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.
 
        
             
        
        
        
Answer:
Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorous, Sulfur (mnemonic for the six most abundant elements in the human body) 
Explanation:
Hope this helped! :3
 
        
             
        
        
        
Answer:
no
Explanation:
we all have diffrant traits from other people
 
        
             
        
        
        
I think the correct answer from the choices listed above is option A. The type of food that should be eaten in limited quantities would be fats. Too much<span> of certain types of </span>fat<span> can lead to other </span>health<span> problems. Hope this answers the question. Have a nice day.</span>
        
             
        
        
        
The plant contains vascular tissue and has an alternation of generation. But, it lacks seeds. So, the plant is a Pteridophyte. 
- Vascular tissues are absent in thallophytes and bryophytes. They are found in pteridophytes, gymnosperms and angiosperms. 
- The sporophyte and gametophyte generation is common in bryophytes and pteridophytes. 
- Seeds are produced in plants that come under the group gymnosperms and angiosperms. The presence of seeds is the main characteristic of these groups. 
- Thallophytes, bryophytes and pteridophytes lack seeds. The reproduction in plants that comes under these groups occurs with the help of spores. 
Thus, the recently discovered species of the plant should be classified based on the presence of vascular tissues, gametophytes and sporophytes. As pteridophytes contain vascular tissues, sporophytes and gametophytes and lack seeds, the plant is a pteridophyte 
Learn more about pteridophytes here: 
brainly.com/question/12375814
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