Answer; 
Vesicles containing neurotransmitter. 
Explanation;
-Neurotransmitters are released by secretion from the ends of axonal terminals.
-Synaptic vesicles store various neurotransmitters that are released at the synapse.
-Neurotransmitters are released from the axon terminal when their vesicles "fuse" with the membrane of the axon terminal, spilling the neurotransmitter into the synaptic cleft.
 
        
             
        
        
        
tree and nest
If a robin builds a nest in a big tree, the robin benefits and the tree
is not helped or harmed. This type of symbiotic relationship is called
commensalism, and it is between the tree and the nest/Robin. 
<span>There are several types of biotic relationships that is occurring every single moment in the ecosystem and commensalism is one. In contrast, parasitism is the biotic relationship where one organism doesn't benefit from the other and is harmed. In this scenario with human beings and mosquitos, this phenomenon of interaction is distinguished as parasitism where mosquitos draws blood that contains nutrients from the human tissue to use it as its source of food and then leaves harmful substances and bacteria in the human’s blood stream.<span> </span></span>
        
             
        
        
        
To help your immune system prepare for diseases
        
                    
             
        
        
        
Answer:
I believe it is the plasma in our bloodstream
Explanation:
plasma holds most of the nutrients in our body and flows in our blood transporting them through our body.