These <span>large leaves of ferns that show multiple venation are called fronds.</span>
        
                    
             
        
        
        
Answer:
Permanent slides ensures preservation of the body parts of the tiny aquatic animals and also also aids good visualization.Most of the exoskeleton of   these tiny   animals are lost during temporary slides preparation, thus loss of visualization.
Because the animals are transfixed to a point, their body parts can not be moved.
It also saves time, energy and resources spent during observation.
However,because of dehydration during preparation  their natural color may be lost which may affect observation of natural features
Explanation:
 
        
             
        
        
        
Flu vaccines need to be revised and changed every year because the flu virus constantly mutates. Flu viruses can change in two ways: drift or shift. Antigenic drift occurs when genes of the virus slowly change during replication until the immune system no longer recognizes it. On the other hand, antigenic shift occurs when a major change in the virus happens. This usually leads to a totally different kind of virus. This is what happened during the H1N1 scare in 2009.
DNA viruses like mumps are less prone to mutation due to the presence of DNA polymerase. RNA viruses are more prone to mutation because they undergo reverse transcription to simulate the role of DNA.
        
                    
             
        
        
        
Tissues form organ and organ forms organ systems,then it’s a complete organism