A. Skeletal and muscular 
the other three don’t have to do with this type of internal movement though as the abdominal region and internal organs don’t have to do with this, A is the only possible answer
        
                    
             
        
        
        
Cell
Tissue
Organ 
Organ System
Organism
        
             
        
        
        
From te options above, the only true statement is :
Today, most scientists believe that both nature and nurture are important in animal behavior
For example  : Imprinting ducks
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Answer: It would probably be A.
Explanation: Abrasion means scraping or wearing away. Therefore the correct sample is probably going to look smaller, smoother, and more even from all the scraping of the river currents.
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Answer:
Red blood cell arrives from the inferior vena cava into right atrium before it passes through the tricuspid valve into right ventricle. It then passes through the pulmonary valve into pulmonary artery before travelling through the lungs and back into the heart, this time the left atrium via the pulmonary vein.
Explanation:
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