This is an example of Precursor gene regulation (protein translation) type of eukaryotic gene regulation.
<u>Explanation:</u>
The source which breakdown proteins into smaller amino acid is pepsin and generated as top cells within stomach lining or membrane, responsible for pepsinogen emission inside stomach. It is represented as zymogen having an extra 44 amino acids linkage as its primary structure. Hydrochloric acid (HCl) releases this zymogen which is emitted from the parietal cells in the stomach lining.
Once food is consumed, the hormone gastrine and the vagus nerve cause the secretion of both pepsinogen and HCl from the stomach lining. Hydrochloric acid induces an acidic environment that allows pepsinogen to unfold in an autocatalytic manner and thus generates pepsin the active form.
 
        
             
        
        
        
Large crystals indicate that it cooled very quickly. If it cooled slowly, it would have time to settle down and make a nice smooth rock.
        
             
        
        
        
Answer:
The correct answer is d) circular folds.
Explanation:
Circular folds slow food going through the small intestine so the villi and microvilli can help the food to be processed and digested properly. Also, the presence of these circular folds increases the surface where the nutrients are being absorbed. 
 
        
             
        
        
        
A combining form meaning  "bone" used in the form of compound words.
For example: british dictionary definition of bone Osteo- before a vowel Oste-
Following are few musculoskeleton combining form:
A                          B
calcane/o calcaneum (heel bone)
femor/o         fumur (thigh bone)
fibul/o         fubula (smaller outer bone of lower leg)
ili/o                  ilium (lateral flaring portion of hip bone)
Hope, so this answer'll help you.........