Question

Use what you know about natural selection to fill in the blanks in the hypothesis. It should answer the lab question, “What is the effect of the type of food available on the frequency of different types of bird beaks?”

Hypothesis: If the type of food available changes, then…
__________
...becuase...
__________

Answer 1

If the type of food available changes, then the types of bird's beaks will change with it, because their bodies are adapting to suit their environmental needs more efficiently. 

Answer 2

Answer: The blank in the question can be filled as-

If the type of food available changes, then over the passage of time, evolution of different beak types will result that reflects adaptation according to the changing food habits because their body wants to adapt in order to survive and reproduce ( pass their genes to the next generation) under the changing conditions.

Therefore, the frequency of allele corresponding to beak will be enhanced or increased.