Answer:
Non-disjunction of chromosomes. 
Explanation:
2 sets of Chromosomes are supposed to be separated into each daughter gamete cells but non disjunction occurred that resulted in both sets of chromosomes being isolated into 1 gamete and the other having no chromosome
 
        
                    
             
        
        
        
Answer:
B. 25%
Explanation:
Assuming the trait for teeth size is represented by the allele A. large teeth size is dominant and will be represented by A while small teeth size will be represented by a.
Assuming that the population of 1,000 [piranhas are all heterozygotes and they crossbreed with one another:
Aa   x   Aa = AA, Aa, Aa and aa
The ration of piranhas with large teeth to that of the small teeth is 3:1 or 75:25.
Hence, about 25% of the next generation of the population is ecpected to have small teeth.
The correct option is B.
 
        
             
        
        
        
Answer:
Meiosis is a type of cell division that reduces the number of chromosomes in the parent cell by half and produces four gamete cells. This process is required to produce egg and sperm cells for reproduction. So basically saying, C is the right answer.
Explanation:
 
        
                    
             
        
        
        
If it is the same dominance as usual it is homozygous
        
             
        
        
        
Answer:
Explanation:
 A boundary that distinguishes inside from outside the cell yet allows materials to enter or leave the cell.
The cell needs a barrier for protection, rigidity and also for easy transportation.