You see first the light wave because light travels faster than sound. Hope this helps
        
             
        
        
        
The Answer is (A) 
Because the pesticide will kill off the bugs and weeds but will damage the soil so after the crops you have in the ground now just will not grow there again until 1 year after the pesticide has washed away
hope I helped
        
                    
             
        
        
        
There are 5 different levels of cellular organization.
Cells, tissues, organs, organ systems and whole organisms. Cells hold genetic material and absorb outside energy. 
Tissues make up the bones, nerves and connective fibers of the body. Organs work to perform specific bodily tasks, such as filtering blood. Organ systems are groups of organs that perform a specific kind of function together, such as digesting food. 
Together, these smaller systems make up an entire living organism which can grow and then go onto reproduce.
Explanation:
 
        
             
        
        
        
Answer:
A. All of these choices are correct.
Explanation:
In pharmacology , drugs play different roles from simple to complex.
as is the above mentioned question drugs can facilitate the transmission of information from one neuron to another so option B is correct.
While the drugs / chemicals can  inhibit the transmission of information from neuron to another so option C is also correct. 
And the drugs can also be used to cure a whole variety of clinical disorders by playing a role at the synaptic level. 
Hence option A All of these choices are correct is the right answer.
 
        
             
        
        
        
I have done GCSE sciences and also applied science a level so I could probably help you :)