Answer:
hi bro mark me ad a brainlist
Explanation:
 snake is the right answer
 
        
             
        
        
        
Through my research I found matching questions with similar answers:
A) macrophages
 B) antigens
 C) antibodies
 D) lymph
The best answer to fill in the blank would be the third option C) Antibodies which in the name anti means against, so since the word anti is the same as against, its a battle between antibodies and invaders, so that's why its C).
        
                    
             
        
        
        
Rainwater picks up carbon dioxide from the air and as it percolates through the soil, which turns into a weak acid. This slowly dissolves out the limestone along the joints, bedding planes and fractures, some of which become enlarged enough to form caves.
        
                    
             
        
        
        
Answer:
Villi
Explanation:
In the small intestine, villi are found present. These villi which appear like a finger-like tissue structure are about 0.5–1.6mm in length in human beings.They have mucosal cells that help in absorption of nutrients. A villus has several microvilli, which increases the surface area of the intestinal wall for faster absorption of nutrients.