Luster means to give shine to a surface. Luster is a general idea of a mineral but you may need to be more specific. By specific I mean what kind of luster does the mineral have? Metallic, Non-Metallic, Vitreous, Resinous, Pearly, Greasy, Silky, or Adamantine. These are more specific types of luster than just saying luster. 
        
             
        
        
        
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Senior mothers are also under pressure to share food with their sons, so that they're able to reproduce as well. It also makes sense for these mothers to assist their sons because as the mothers grow older, they are increasingly related to whales in other, neighboring pods via their sons' calves.
 
        
             
        
        
        
The biology in which we study about the life of marine and what they eat and how they eat..ig thats how i will explain idk
        
                    
             
        
        
        
I believe the answer is b hope this helps
        
             
        
        
        
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The first line of defence (or outside defence system) includes physical and chemical barriers that are always ready and prepared to defend the body from infection. These include your skin, tears, mucus, cilia, stomach acid, urine flow, 'friendly' bacteria and white blood cells called neutrophils.
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