I honestly don’t know but I believe it’s A
        
                    
             
        
        
        
hi I just need brainliest answer 
I think good insulator
 
        
             
        
        
        
One of the possible effects of increased carbon dioxide concentration on our planet would be a warmer climate.
<h3>Greenhouse effect</h3>
Carbon dioxide is one of the numerous greenhouse gases that exist in nature. The gases are responsible for the warming of the planet.
Carbon dioxide and other greenhouse gases form a blanket layer in the atmosphere and trap some of the reflected solar radiations from the sun, preventing them from escaping back to space.
The more the concentration of greenhouse gases in the atmosphere, the more the solar radiation that is trapped and the warmer the earth gets. 
More on greenhouse effects can be found here: brainly.com/question/13706708
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1.The presence of valves 2.the milking action of skeletal muscles 3. the veins as the muscles contract
 
        
             
        
        
        
I think the answer is true, I hope this helps friend.