Internal means its on the inside 
external means its on the outside 
so an internal regulator is when the proteins respond to events on the inside of a cell 
and an external regulator is when the proteins respond to events outside the cell
        
                    
             
        
        
        
Carbon dioxide fluctuations occur for different seasons of the year due to the presence of plants in an area.
<h3>Why carbon dioxide fluctuations occur for different seasons of the year?</h3>
The carbon dioxide levels in the atmosphere moves up and down every year when plants use carbondioxide gas through the process of photosynthesis and respiration. Plants take up the carbondioxide gas in the spring and summer season and release it in fall and winter season. In this modern world, the level of carbon cycle is increasing because more carbon dioxide is emitted from burning fossil fuels and other human activities.
So we can conclude that carbon dioxide fluctuations occur for different seasons of the year due to the presence of plants in an area.
Learn more about season here: brainly.com/question/15734021
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Answer:
True
Explanation:
Humans have 23 pairs of chromosomes, for a total of 46 chromosomes.
 
        
             
        
        
        
Answer:
20 minutes 
Explanation:
Divide distance by speed to get time
D/S = t
350/17.5 = 20
(Just an fyi you posted this in biology)