Answer:
<u><em>The correct option is C) Meiosis produces 4 daughter cells each with half the number of  chromosomes of the original cell.</em></u>
Explanation:
There are two main processes by which cell divides:
1) Mitosis
2) Meiosis
All the cells of the body divide by the process of mitosis except the sex cells.<em> Sex cells divide by the process of meiosis.</em>
Meiosis can e described as a type of cell division in which four daughter cells are formed each having half the number of chromosomes as the parent cell. This is because the cell has to attain half of the maternal and half of the paternal chromosomes at the time of fertilization.
Crossing over and independent assortment are the phenomenon of meiosis which bring genetic diversity among parent and children. 
 
        
                    
             
        
        
        
Given question is incomplete. Complete question has been attached.
Answer:
C. Excessive potassium has diffused out causing hyperpolarization.
Explanation:
The nerve action potential can be divided into following stages:
- Stimulus is detected by the cell in resting stage.
- Sodium channels in the membrane open from where influx of sodium ions occur which is called depolarization
- After a while, sodium channels close and potassium channels open from where efflux of potassium ions occur which is called repolarization.
- The membrane potential further lowers due to continous efflux of potassium ions which is called hyperpolarization.
- After a while potassium channels close and membrane returns to its resting stage.
In the given figure, stage 4 depicts hyperpolarization because the membrane potential has dropped to the lowest point below -70mV. Hence, option C is correct. 
 
        
             
        
        
        
I believe the answer is B
        
                    
             
        
        
        
The substance must be able to alter its physical characteristic (for example, its color) in accordance to a change in pH. One example of this is litmus paper, which becomes red under acidic conditions and blue under basic conditions.