Fight or flight, because according to Hans Selye, this occurs at times of danger when your adrenaline is heightened.
        
             
        
        
        
Answer:
Chromosomes become visible, crossing-over occurs, the nucleolus disappears, the meiotic spindle forms, and the nuclear envelope disappears.
Explanation:
The duplicated homologous chromosomes pair, and crossing-over (the physical exchange of chromosome parts) occurs.
 
        
             
        
        
        
Answer: A) They are the site of protein synthesis.
Explanation:
Ribosomes are small round organelles attached to the endoplasmic reticulum in cells, and serve as site of protein synthesis. This is possible because the transfer RNA assembles amino acids to form polypeptide chains right in the ribosomes.
Thus, ribosomes are site of protein synthesis 
 
        
             
        
        
        
Answer:
By the amount of silica
cause igneous rock is classified by their color, texture and chemical composition