Finches adapt to the new conditions such as drought by changing the size, shape and depth of their beaks. Beak morphology varies according to drought conditions. Since after the drought, vegetation dries out and the hard, big, tough seeds remain, only the finches with deep beaks will survive. Finches adapt via their beaks to different foods sources and different local conditions.
 
        
                    
             
        
        
        
Answer:
1. Signaling molecule
2. Signaling receptors 
Explanation:
Hormones, growth factors, neurotransmitters, etc. serve the function of signaling molecules for cells. These molecules are released by one cell and bind to the receptors present on/in the target cells to elicit the desired response. Thereby, the signaling molecules serve in cell-cell communication. 
For example, insulin hormone synthesized and released from beta cells of pancreas binds to its cell surface receptors present on the surfaces of liver cells and muscle cells to stimulate the uptake of the glucose from the blood.  
Likewise, neurotransmitters released from the presynaptic neuron bind to receptors present on the membrane of postsynaptic neuron and serve to carry the nerve impulse to the postsynaptic neuron.  
 
        
             
        
        
        
Thank you for posting your question here at brainly. Below is the solution for the above problem. I hope it helps. 
period of orbit at 26000 AU 
<span>P = a^(3/2) </span>
<span>= (26000)^(3/2) = 4,192,374 years (Earth)</span>
        
             
        
        
        
3, definitely. The other answers are all harmful to the environment or flat-out wrong. At least it gets the economy going and lets more people make a living... even if it's hurting the ozone.