Answer
(a) is the correct option
explanation :
Hair cells are the sensory receptors of both the sound related framework. hair cells distinguish development in their environment any damage in these hair cells can bring about the lowering hearing capability, and this defect is changeless. calcium ion is an imperative part of the hair cells to adjust the intensification of the signal. 
 
        
             
        
        
        
Answer:
a prezygotic barrier
Explanation:
Both wild tigers and lions are said to be reproductively isolated.
Reproductive isolation is defined as the existence of barrier between organisms of different species such that they cannot reproduce. 
The mechanisms of reproductive isolation varies. While some act to prevent the formation of zygotes (in case of mating) between organisms of different species, some ensures that the resulting zygotes are invalid. 
Reproductive isolation mechanisms that act to prevent fertilization and formation of zygotes are referred to as prezygotic mechanisms while those that ensure that invalid zygotes result (in case of successful fertilization) are referred to post zygotic mechanisms.
<em>The natural differences in the ranges of wild tigers and lions ensure that both animals do not mate with each other, let alone results in zygote. This is a form of pre-zygotic reproductive isolation mechanism.</em>
 
        
             
        
        
        
Answer:
1) 60x; 2) 150x
Explanation:
Total magnification = Power of the Ocular X Power of the objective
Power of Ocular = 15x
Power of Objective = 4x ; 10x
1)Total magnification = 15 X 4 = 60x
2)Total magnification = 15 X 10 = 150x
 
        
             
        
        
        
I think it's B an injury to the central nervous system.
        
                    
             
        
        
        
From the deepest to most superficial: pia mater, arahnoid, dura mater