Answer:
sorry
Explanation:
 I don't know the answer this is really confusing but I am really sorry you have to do this. 
 
        
             
        
        
        
Protostars are less dense than other stars.  
Explanation:
Protostars are very young ‘stars’ made from hydrogen clouds that are beginning to coalesce and collapse under their weight. The hydrogen has not even begun fusing. Therefore, they are mainly made of hydrogen which is the lightest element in the universe.
Stars, however, have begun fusing hydrogen to other heavier elements like helium, carbon, oxygen, and iron. The elements are much heavier than hydrogen making other stars much denser than protostars. 
Learn More:
For more on protostars vs stars check out;
brainly.com/question/3719157
brainly.com/question/2229892
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- Endothermic reaction means the reactant side takes heat from surrounding and get decomposed i.e ∆H=-ve
- If the equation is exothermic then it means the reactant is happy to decompose .But it's not as it's endothermic
Now
- HgO is Omitted from our solution option.
Hg is a atom so no bonds hence no bond strength occurs.
- O_2 is a molecule and so it's our answer .
 
        
             
        
        
        
Answer: Option (1) is the correct answer.
Explanation:
Compounds are the substances which contain two or more different elements. 
Similarly, water is a compound as it is made up when two hydrogen atoms combine with one oxygen atom. Compounds can be broken down with the help of chemical reactions. 
Hence, the statement water can be broken down by chemical means explains why water is classified  as a compound.
 
        
                    
             
        
        
        
Answer:
heat is the movement from areas of <u>high </u>temperature to areas of <u>low </u>temperature