Answer:
A. people from different cultures and living at different times can contribute to scientific knowledge.
Explanation:
 
        
             
        
        
        
Most of all cell enzymes are proteins
 
        
             
        
        
        
Trilateration Measures Distance, Not Angles
Using a simple two-dimensional example, let's imagine we have three GPS satellites each with a known position in space. ... This means that the distance could be anywhere on that circle. But this time, we have two known distances from two satellites.
        
             
        
        
        
The correct answer is electrons.  
Electron transport chain refers to an array of complexes, which mediates electrons from electron donors to electron acceptors through redox reactions, and combines the transfer of electrons with the transfer of protons through a membrane.  
This produces an electrochemical proton gradient, which instigates the production of ATP. The ultimate electron acceptor in the electron transport chain is oxygen in aerobic respiration and sulfate in anaerobic respiration.