Answer:
The first one and the last one.
Explanation:
Carbon dioxide is generated by cellular respiration and released into the atmosphere.
Photosynthesis makes oxygen that plants can release into the atmosphere.
 
        
             
        
        
        
Given reactions:
(A)   6CO2(g) + 6H2O(l) + sunlight → C6H12O6(aq) + 6O2(g)
(B)  2H2(g) + O2(g) → 2H2O(g) + energy
Exothermic reactions are those which proceed with the release of heat/energy. In contrast, endothermic reactions proceed with the absorption of energy in the form of heat or light.
Since reaction A required sunlight, it is endothermic. Reaction B releases energy, hence exothermic
Ans: (B) 
A is endothermic
B is exothermic
 
        
             
        
        
        
The structure of the alkyl bromides used in a malonic ester synthesis of ethyl 2-methyl-4-pentenoate are as drawn in the attached image.
<h3>Ethyl 2-methyl-4-pentenoate by Malonic ester synthesis.</h3>
The malonic ester synthesis is a chemical reaction characterized by the alkylation of diethyl malonate or a similar ester of malonic acid at the carbon alpha (directly adjacent) to both carbonyl groups, and subsequently converted to a substituted acetic acid.
Hence, it follows from the structure of Ethyl 2-methyl-4-pentenoate that the alkyl bromides used are Ethyl bromide and methyl bromide.
Read more on Malonic ester synthesis;
brainly.com/question/17237043
 
        
                    
             
        
        
        
Answer:
7 is the mass number of li and 3 is the atomic number 
a 3
b 7
c 3
d 4 
 
        
             
        
        
        
Answer:
Shivering. 
Explanation:
Homeostasis is the bodies need to keep things at a normal. When you are cold you shiver to produce body heat and get back to normal