Hollow lightweight bones benefit the bird by letting it fly. If the bird had regular bones like any other animal, then the bird wouldn't have the ability to be able to fly due to the extra weight.
        
             
        
        
        
North component: y = 15.0 m * sin 55.0º = 12.3 m West component: x = 15.0 m * cos 55.0º + 7.00 m = 15.6 m 
so his heading, measured from West, is Θ = arctan(y/x) = arctan0.787 = 38.2º N of West 
and measured from North is φ = arctan(x/y) = arctan(1.27) = 51.8º W of North 
Hope this helps!
        
             
        
        
        
Answer:
a chlorophyll
Explanation:
chlorophyll is the pigment in chloroplast that gives it its green color
 
        
             
        
        
        
Answer:
smooth muscle and cardiac muscle only.
Explanation:
because all of these muscles are involuntary meaning all of these muscles are not moveable by choice, you can not decide when to move these muscles. Foe example we can not control the heart muscles, the heart needs to pump involuntary, but the other muscles from the list we have control over. For example we can make a choice when it comes to moving some skeletal muscles, but not a choice when moving smooth muscle and cardiac muscle .