I think it's called a hypothesis 
        
             
        
        
        
Sponges are similar to other animals in that they are multicellular, heterotrophic, lack cell walls and produce sperm cells. Unlike other animals, they lack true tissues and organs, and have no body symmetry.
The shapes of their bodies are adapted for maximal efficiency of water
flow through the central cavity, where it deposits nutrients, and leaves
through a hole called the osculum. Many sponges have internal skeletons of spongin and/or spicules of calcium carbonate or silicon dioxide. All sponges are sessile
aquatic animals. Although there are freshwater species, the great
majority are marine (salt water) species, ranging from tidal zones to
depths exceeding 8,800 m (5.5 mi).
        
                    
             
        
        
        
Primary succession is when, for example, a volcano explodes and there is nothing left and even the soil is ruined. It would take at least a hundred years for the land to be like it was before the volcano erupted. Secondary succession is when, for example, a wild fire happens but the soil is not ruined. It would take at least 25-50 years for the land to be like it was before the fire.
        
             
        
        
        
Answer:
I think that Viruses are not alive so Being composed of molecules that are found in cells (nucleic acids, proteins, lipids and complex sugars) and having the capacity to evolve, viruses are often said to be alive. But they aren't alive because they arent a living thing.
 
        
             
        
        
        
Answer:
<h3>Recently been reviewed and range from single cell protein </h3>
Explanation:
I hope it is correct