Halite or sulfur or gold or silver 
        
             
        
        
        
Answer:
13.18 m/s
Explanation:
Let the velocity of sports utility car is
 -u as it is moving in opposite direction.
mc = 1200 kg, uc = 31.1 m/s
ms = 2830 kg, us = - u = ?
Using conservation of momentum
mc × uc + ms × us = 0
1200 × 31.1 - 2830 × u = 0
u = 13.18 m/s
 
        
             
        
        
        
Answer:
B. chemical only.
Explanation:
In the process of respiration which is a chemical process where organic compound is released. In this process exergonic reaction takes place in which compound changes into different ones.
Following are the two types of respiration:-
1] Aerobic respiration:- In this type of respiration requirement of oxygen is more and energy released is more.
2] Anaerobic respiration:- In this type of respiration oxygen requirement is less and energy released is also less.