the answer is A according to my knowledge.
        
             
        
        
        
Carbon dioxide is transported in the blood in three ways: (i) dissolved in solution; (ii) buffered with water as carbonic acid; (iii) bound to proteins, particularly haemoglobin. Source: https://academic.oup.com/bjaed/article/5/6/207/331369 
 
        
             
        
        
        
<span>Vascular  is it i think =)</span>
        
             
        
        
        
Answer:
Single celled organism that love moisture is yeast. 
Explanation:
Yeast is a single cell organism that is grouped with kingdom fungi. The commonly known yeast is <em>Saccharomyces cerevisiae </em>that is used for baking and brewing industry. Yeast fermentation requires moisture and a warm environment. The moisture and carbohydrates are hydrolyzed during fermentation process to the simple sugars.