These are the Kepler's laws of planetary motion.
This law relates a planet's orbital period and its average distance to the Sun. - Third law of Kepler.
The orbits of planets are ellipses with the Sun at one focus. - First law of Kepler.
The speed of a planet varies, such that a planet sweeps out an equal area in equal time frames. - Second law of Kepler.
 
        
                    
             
        
        
        
Answer:
All
Explanation:
I'm not sure what you meant but Newton's third law which basically states that every action has an equal and opposite reaction applies to <em>all</em> objects. So I think the answer is all.
 
        
             
        
        
        
Answer:
D 
Explanation:
D) The overall work done by gravity is zero  
This statement is correct . 
If m be the mass of each of the children and h be the height of tower 
work done by gravity on the boys in going up = - mgh 
it is so because force applied by gravity = mg downwards and displacement 
is upwards 
work done will be negative = - mgh 
Work done by gravity on boys when they come down = + mgh because both force and displacement are downwards .
Hence total work done = - mgh + mgh = 0. 
The children will have same kinetic energy as the inclined surface is friction-less so no energy will be dissipated hence addition of energy to boys in both the cases will be same. 
 
        
             
        
        
        
Answer:
Explanation:
Neurons communicate via both electrical signals and chemical signals. The electrical signals are action potentials, which transmit the information from one of a neuron to the other; the chemical signals are neurotransmitters, which transmit the information from one neuron to the next.
The electrical signal travels down the axon to the axon terminals where it tells the vesicles to release the neurotransmitters into the synaptic cleft which travel to the receptors of the receiving cell which releases the second messengers