Answer:
D
Explanation:
The item labeled 2 is the cell capsule that protects the cell from engulfment by eukaryotic cell, such as macrophages.
 
        
             
        
        
        
Answer:
option B is correct
Explanation:
the effect of external physical factor on cell division is clearly seen on in density dependent inhibition( a phenomenon in which crowded cell  stop dividing) 
 
        
             
        
        
        
Answer: Option B.
Neural crest and peripheral nervous system.
Explanation:
Neural crest are bilateral paired cells of the neural tube that arise from the ectoderm layer of the embryo. Thesescells move to different part of the body and differentiate into various cell types like melanocytes,cartilage and bone, smooth muscle, craniofacial, neurons, gangalia e.t.c. The neural crest running through neural tube develop into peripheral nervous system after birth. Peripheral nervous system consist of neurons and gangalia outside the nervous system The peripheral nervous system connect the central nervous system to organs, skin and limbs.
 
        
             
        
        
        
The correct answer is peroxisomes.  
Peroxisome refers to a small organelle found in the cytoplasm of various cells that comprises catalase (the reducing enzyme) and generally some oxidases.  
They are the minute vesicles and comprises the digestive enzymes used for dissociating toxic components in the cell. They are not similar to lysosomes on the basis of the kind of enzymes they withheld. The peroxisomes generally contain enzymes that need oxygen, that is, oxidative enzymes.