Answer:
A)  A decrease in Na+ permeability, and an increase in K+ permeability.
Explanation:
When the potential action reaches a peak of about +40 mv Na+ channels are open and a high number of Na+ ions are entering the inside of the cell. Shortly after this happens the K+ channels will start to open their gates increasing the cell  K+ permeability  while the Na+ channels will start to close their gates, so the Na+ permeability will decrease. This happens  in order to valance the positive charge on the inside of the cell. Normally the inside has a negative charge while the outside has a positive one, as the inside is more positive due to the increase in Na+ permeability at the beginning of the potential action, K+ cations (which are in abundance in the cell) will have to go out through the K+ channels  so as to restore the charge valance, that means that there is an increase in K+ permeability. 
 
        
             
        
        
        
Answer:
antibiotics
Explanation:
pesticides have to do with nature and killing bugs, weeds, etc. Irrigation has to do with watering plants and people. Trucks are vehicles that transport. Antiobiotics help kill bad bacteria in your body when your sick, so that's health related. 
 
        
             
        
        
        
Answer:
don't know for sure sure but i would think branching
Explanation:
I think this cause of subspecies ( Bengal, Sumatran and Siberian tigers)