Answer:
A
Explanation:
Quaternary structure of proteins is composed of two or more polypeptide chains. Insulin has two; one alpha  and one beta chain. The two chains are joined together by disulfide bonds at two points (at cysteines). Other examples of quaternary proteins structures are DNA polymerase and hemoglobin. 
 
        
             
        
        
        
Answer: 1.414x10^24 molecules in 94.4g MgO
Explanation: molar mass MgO 40.204
molecules in 40.204 g MgO = avogadro number
molecules in 94.4 g MgO = (94.4/40.204)*avogadro number
(94.4/40.204)*6.02214076*10^23 = 14.14x10^23
 
        
             
        
        
        
Acids: taste sour, has a pH less than 7
bases: tastes bitter, has a pH greater than 7
        
             
        
        
        
Answer: 13 grams
Explanation:
The quantity of heat energy (Q) released from a heated substance depends on its Mass (M), specific heat capacity (C) and change in temperature (Φ)
Thus, Q = MCΦ
Since,
Q = 202.8 Joules 
 Mass of silver = ?
C = 0.240 J/g °C.
Φ = 65°C
Then, Q = MCΦ
202.8J = M x 0.240 J/g °C x 65°C
202.8J = M x 15.6 J/g
M = (202.8J / 15.6 J/g)
M = 13 g
Thus, the mass of silver is 13 grams