Given that I no not see any explanation in the previos answer, I think you can benefit of this.
Exothermic refers only to the fact that the reaction releases energy in the form of heat when occurs. So, the enthalpy is higher at start and lower and the end.
Seen in this way, you can deduct that the change in enthalpy is negative, which is what the third option says.  
        
                    
             
        
        
        
Answer:
U=19
A=8
B=5
Step-by-step explanation:
Cardinality refers to the number of elements in a set.
 
        
             
        
        
        
Answer:
Option B
Option E
Step-by-step explanation:
By the use of following postulates we can prove the two right triangles to be congruent.
1). HA - [Equal hypotenuse and an cute angles]
2). LL - [Two legs should be equal]
3). LA - [One leg and one angle must be equal]
4). ASA - [Two angles and the side containing these angles should be equal]
In the given right triangles,
1). OJ ≅ IL
2). ∠O ≅ ∠I
3). ∠J ≅ ∠L
Therefore, two postulates HA, ASA will be applicable for the congruence of the two triangles given.
Options A and E will be the answer.
 
        
                    
             
        
        
        
Your answer would be C. 27/190. 
This is because the probability of choosing green as the first marble would be 9/20, as there are 20 marbles in total and 9 of those are green.
The probability of choosing a red marble as the second marble would be 6/19, as no red marbles would have been lost if green was picked first, but there would be one less marble in total.
The 'and' rule for probability, the one that is used to determine the probability of P(A) and P(B), is to multiply, so we need to do 9/20 × 6/19 = 54/380 = 27/190.
I hope this helps!
        
             
        
        
        
Answer:
Third option 
O 100 cm
1m
Step-by-step explanation:
