Complete Question:
Which of the following might stimulate the cephalic phase of gastric secretion?
A. stomach distention
B. the production of saliva
C. the thought of food
D. the production and secretion of gastrin. 
Answer:
C. the thought of food
Explanation:
Gastric secretion usually occurs in three different phases, namely;
- Cephalic 
- Gastric 
- Intestinal 
The thought of food usually stimulate the cephalic phase of gastric secretion in organisms. The presence of lipids or low pH inhibits Gastric secretion during the intestinal phase. 
 
        
             
        
        
        
Mechanical stress applied to bone increases osteoblast activity in bone tissue, and the removal of mechanical stress decreases osteoblast activity.
Explanation:
Osteoblasts are cells , that are produced in the bone marrow and are responsible for formation of bones and bone matrix.
Whenever a mechanical stress is applied on the bones , a series of reactions are triggered. As a result the activities of osteoblast increases to synthesize more and more bone matrix to provide strength.
Again on the other hand a decrease in mechanical causes a decrease in the activities of the osteoblasts.
 
        
             
        
        
        
Answer:
The force of gravity can cause erosion by;
- pulling rocks and other particles down the side of a mountain or cliff
- it can cause landslides which significantly erode an area.
 
        
             
        
        
        
It helps sustain tbe population because of the food chain. everything needs to eat, so the more diverse a population is, the more options things have to eat. The population is sustained because everything is able to eat to survive
        
                    
             
        
        
        
Answer:
A
Explanation:
The top answer is correct, over time it has become weaker.