An organ within an organism accomplishes tasks. To engage in these tasks, an organ typically requires energy provided by other organisms.
B
interaction with other organ systems.
С
communication with other organisms.
D
segregation from other organ systems.

I think that it is the first one :)

Explanation:

Pls pls tell me if  im wrong, ill do my best to fix it

if the type of the food available changes, then the frequency of beak types will change, because birds with beaks more suited to the available food will be more successful over time.