Collection fits into the water cycle because of how all the water molecules collect in the clouds
        
             
        
        
        
The pneumatic bones are important to birds for respiration. They are hollow bones which are connected to the bird's respiratory system and are important for birds to be able to breath. Examples of pneumatic bones are the skull, humerus, clavicle, keel (sternum), pelvic girdle, and the lumbar and sacral vertebrae.
        
                    
             
        
        
        
<span>I believe it is light, but this is kind of a confusing question. Technically there is a independent and dependent variable in the question. The variable being manipulated is light, and the earthwork activity depends on the light. </span>
 
        
                    
             
        
        
        
Answer:
- covers and lines body surfaces
- minimal intercellular substance 
- cells are densley packed together
- cells rest on basement membrane 
- simple (single line of cells) and stratified (multiple layers)
- squamous (oval like shape), cuboidal (cube shape), columnar (long rectangle shape) 
- vascular (tissue doesn't have its own blood supply)
Explanation:
Hope this helps!