True, major events like a super volcano's or asteroid strikes can send tons of ash dust and debris into the stratosphere and cause global cooling. <span />
        
             
        
        
        
The nucleus is an organelle found in eukaryotic cells. Inside its fully enclosed nuclear membrane, it contains the majority of the cell's genetic material. This material is organized as DNA molecules, along with a variety of proteins, to form chromosomes. 
 
        
             
        
        
        
The correct answer is the spores. Fungi reproduce asexually by budding, fragmentation, or spore production. Fragments of hyphae can grow new colonies. Mycelial fragmentation occurs when a fungal mycelium separates into pieces with each component growing into a separate mycelium. Spores are usually haploid and unicellular and are produced by meiosis in the sporangium of a diploid sporophyte. 
        
             
        
        
        
The second one I believe.
        
                    
             
        
        
        
Answer:
d) do all jobs for survival
Explanation:
A single cell perform all its activity on its own.