Answer: C. 1.8
Steps:
25x = 45
x = 45/25
x = 1.8
        
             
        
        
        
Answer:
The correct answer is - 4. ttPp
Explanation:
Given - tall is dominant over short pea plant
let assume T is dominant and t is short which is recessive
Similarly, P for dominant purple flower and p for white flower
The offspring has a short plant which means it has both t allele or recessive allele for the height of a plant by the cross of a true-breeding purple and true-breeding white:
     P   P
p   Pp Pp
p   Pp Pp
This means the offspring would have a heterozygous case for the genotype of the flower of the pea plant
Thus, the correct answer is ttPp
 
        
             
        
        
        
The major function of the contractile vacuole of amoeba is osmoregulation. The solute concentration found in the cell of amoeba's cytoplasm is more than the solute concentration in the freshwater that surround the external part of the organism, thus, water enter the cell through osmosis. The contractile vacuole collect the excess water and expel it through an opening in the cell membrane. By doing this, the contractile vacuole maintains the water balance in amoeba. This how the contractile vacuole normally operate.
In a situation where amoeba is placed in seawater, then water from the cell cytoplasm will rush out of amoeba cell, because of the higher salt content of the surrounding medium. The contractile vacuole will respond to the situation by increasing its contraction and pumping water out the cell in an accelerated manner, this will lead to the shrinking of the cell. 
 
        
             
        
        
        
D.
Both organisms have the same genus in their scientific name meaning they are members of the same family and order.
 
        
             
        
        
        
Answer:
Option D, Zero out of four (0%)
Explanation:
As we know,  achondroplasia is an autosomal dominant pattern. Now a girl having normal stature mate with a partner who also has a normal stature. 
Thus let us assume -
Allele for disproportionately short arms and legs be represented by "A"
while allele for normal stature be represented by "a"
Now genotype of parents would be 
Female - aa
Male - aa
Thus, 
aa x aa
aa, aa, aa, aa
Thus, option D is  correct.