It should be transport of waste but I’m not 100% sure :(
        
             
        
        
        
Explanation:
charles darwin proposed thoery of natural selection.he had collected imnumerable specimens of plant and animals.he published concept survival of fittest. while explaining he says that There is always competition for food.only those organism survive which shows adptations in various reasons. it thoery of natural selection. 
There are some objections, 
1. natural selection is not only factor responsible for evolution. 
2. darwin did not mention uesful and useless modifications. 
3. There is no explanation about slow and abrupt changes 
 
        
             
        
        
        
When a human dies, his corpses gets decomposed by decomposing bacteria. What's produced by the decomposing bacteria is the "fertilizer" for plants.
        
             
        
        
        
Answer:
(a) Allow movement in only one plane/direction (that is extension or flexion)
(b) The skeletal system also produces blood cells in their bone marrow
 
        
                    
             
        
        
        
Answer:
ok where is it
we can help only if there is something attached