Answer:
There needs to be enough sea urchins for otters to come and there needs to be enough otters to eat the urchins.
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Answer:
A mass of nutrients enters a stomach full of strong, hydrochloric acid. The acid gets rid of all of the waste material, which is then expelled.
Explanation:
 
        
                    
             
        
        
        
Answer: hope this helps :)
The motion of air mass motion is usually based upon the air flow in the upper atmosphere. As the jet stream changes intensity and position, it affects the motion and strength of air masses. Where air masses converge, they form boundaries called "fronts".
3-D view of a cold front.
Fronts are identified by change of temperature based upon their motion. With a cold front, a colder air mass is replacing a warmer air mass. A warm front is the opposite affect in that warm air replaces cold air. There is also a stationary front, which, as the name implies, means the boundary between two air masses does not move.
The motion of air masses also affects where a good portion of precipitation occurs. The air of cold air masses is more dense than warmer air masses. Therefore, as these cold air masses move, the dense air undercuts the warmer air masses forcing the warm air up and over the colder air causing it to rise into the atmosphere.
So, fronts just don't appear at the surface of the earth, they have a vertical structure or slope to them as well. Warm fronts typically have a gentle slope so the air rising along
 
        
             
        
        
        
Answer:
The correct answer would be -
If the type of food available changes, then the frequency of beak also changes because the beak of the bird suited to food will survive successfully.
Explanation:
According to the theory of natural selection, an organism that is able to adapt according to the change in the environment, it helps in their survival and increases their number in the system.
It is given that the type of food available is changing, so it will lead to the change in the frequency of bird beaks in that particular area. So, if they adapt to survive under the changes in the available food type, otherwise not be able to survive and die.
So,
If the type of food available changes, then the frequency of beak also changes because the beak of the bird suited to food will survive successfully.
 
        
             
        
        
        
Cell theory is one of the foundations of biology. The observation of Robert Hooke,Anton Van Leeuewenhoek,Matthias Schleiden,Theodor Schwann,Rudolf Virchow, and others led to the devolepment of the cell theory.