As you did not state what the question is you just wrote a statement, I am guessing this is a True or False question. If there is more to the question please comment and Id be happy to help you answer more but if this is T/F then Ill answer it here right now.
A main-sequence star maintains a stable size as long as there is enough hydrogen to fuse into helium. True or False?
Answer:  True
Hope this Helps, good luck, and comment if you need help on anything else :)
 
        
             
        
        
        
To answer this question, let us first mention what is food danger zone. Well, this refers to the temperature range in which bacteria grows faster in the food. The range is defined as 30 to 140 degree Fahrenheit or can be converted into 4 to 60 degree Celsius. Going back to the question, the maximum number of hours that a food can be held in the food danger zone is only 2 hours. Beyond this 2  hours, the food is not safe to be eaten and the person who dares to eat this food might get some illness and worst might experienced food poisoning.
        
                    
             
        
        
        
Uracil (U) is not part of DNA but is part of RNA 
        
                    
             
        
        
        
A and B can react to form C and D or, in the reverse reaction, C and D can react to form A and B. This is distinct from reversible process in thermodynamics.
Weak acids and bases undertake reversible reactions. For example, carbonic acid: H2CO3 (l) + H2O(l) ⇌ HCO−3 (aq) + H3O+(aq).
The concentrations of reactants and products in an equilibrium mixture are determined by the analytical concentrations of the reagents (A and B or C and D) and the equilibrium constant, K. The magnitude of the equilibrium constant depends on the Gibbs free energy change for the reaction.[2] So, when the free energy change is large (more than about 30 kJ mol−1), then the equilibrium constant is large (log K > 3) and the concentrations of the reactants at equilibrium are very small. Such a reaction is sometimes considered to be an irreversible reaction, although in reality small amounts of the reactants are still expected to be present in the reacting system. A truly irreversible chemical reaction is usually achieved when one of the products exits the reacting system, for example, as does carbon dioxide (volatile) in the reaction