The cardiac sphincter which is
found at the upper part of the stomach guards the entry of food into the
stomach. Cardiac sphincter performs essential roles in digestion as it keeps
stomach acids and other stomach contents from pushing up and into the
esophagus.
 
        
             
        
        
        
Answer:
Gram negative bacteria don't retain purple color as they contain thin cell wall which is composed of peptidoglycans present between inner cytoplasmic cell membrane and bacterial outer membrane.
Explanation:
They contain some characters like-
- The outer membrane is important as it protects them from antibiotics,detergents that damages the peptidoglycans of cell membrane.
- The outer membrane is composed of lipopolysaccharide that secrets lipid A component which causes toxic reaction.
- This toxic reaction creates different health hazards like high fever,increase respiratory rate,low blood pressure etc.
- Braun's lipoprotein present between outer membrane and peptidoglycans by a covalent bond.
 
        
             
        
        
        
B because yea this has to be 20 letters long
        
                    
             
        
        
        
 The motor neuron carries the nerve impulse.
↓
The nerve impulse reaches the neuromuscular junction.
↓
Calcium ions release into the myofibrils.
↓
Myosin and actin protein filaments attach to each other.
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Myosin filaments pull on the actin filaments.
↓
The sarcomere shortens.
The neurotransmitter (ACh) from motor neurons signals a muscle fiber to depolarize. The depolarization (Na+) will trigger Ca++ release and will initiate contraction by binding to troponin. Myosin pulls the actin strands. ATP sustains the contraction.
 
        
             
        
        
        
Platelets are fragments of large, multinucleate megakaryocytes.  
An important function of platelets is to <span>transport clotting factors. 
</span>Platelets form a plug to help prevent blood loss in situation in which blood vessel is damaged. They play a central role in the clotting cascade.