Answer:
Light energy or chemical energy
Explanation:
Light energy or chemical energy support the whole pyramid. Without it, plants/producers would die (they wouldn't be able to photosynthesize or chemo synthesize), leaving the first level consumers with no food, thus leaving the second level consumers with no food, and so on. 
Hope this helped!
 
        
                    
             
        
        
        
<h3><u>Answer;</u></h3>
Label A; Mitochondria.
Label B; Nucleus.
Label C; Golgi apparatus.
Label D; Rough endoplasmic reticulum 
<h3><u>Explanation;</u></h3>
- All the above are various organelles in a eukaryotic cells each carrying different cellular activity to enhance the functioning of a cell.
Label A; Mitochondria.
- <u>Mitochondria</u> is the powerhouse of the cell which converts glucose to energy rich molecules of ATP, through the process of cellular respiration.
Label B; Nucleus.
- <u>Nucleus</u> contains the genetic material or DNA, RNA , nucleolus, chromatin fibres and proteins. It contains the chromosomes which control the hereditary characteristics.It also regulates all the activities of the cell.
Label C; Golgi apparatus. 
- <u>Golgi apparatus;</u> they are also called Golgi bodies. They function in modifying, sorting and packaging of proteins for secretion. They are also involved in the transport of lipids around the cell, and the creation of lysosomes.
Label D; Rough endoplasmic reticulum 
- <u>The rough endoplasmic reticulum</u> provides surface for protein synthesis. It is also used to transport cellular contents from one cell to another.
- The risbosomes attached on the rough endoplasmic reticulum are resposible for the protein synthesis through the process of translation.
 
        
        
        
<span>Chromosomal abnormalies effect all of the bodies cells. Certain anomolies effect different body parts in different ways. One anomily may effect the heart and the other vision or hearing. Hope this helps. Have a nice day. Feel free to ask more questions.</span>
        
             
        
        
        
Flucuated between hot and cold periods
        
                    
             
        
        
        
Answer:
Hydrogen Bonding in Water (1) The hydrogen bond in water is a dynamic attraction between neighboring water molecules involving one hydrogen atom located between the two oxygen atoms.
Explanation: