Oxygen. Plants need water sunlight and CO2 to make their food. They get the carbon and the energy from the CO2 and the sun, and they need water as well. Then they release oxygen
        
             
        
        
        
Answer:
(d) a net external force must be acting on the system 
Explanation:
Momentum is given as the product of mass and velocity.
P = MV
According to Newton's second law of motion, " Force applied to a body (system) is directly proportional to the rate of change of momentum of the body (system) which takes place in the direction of the applied force (external force).
F ∝ΔMV
Therefore, If the total momentum of a system is changing, a net external force must be acting on the system.
 (d) a net external force must be acting on the system 
 
        
             
        
        
        
Okay!  Thank you for this knowledge
        
             
        
        
        
Answer: The law of conservation of energy states that energy can neither be created nor destroyed - only converted from one form of energy to another.
Explanation: