Mammalia (mammals) have hair or fur and produce milk
The amount of light with not effect the rate of photosynthesis
The answer is A. - Prokatyotic cells lack a defined nucleus while eukaryotic cells do have one :) I loved learning about the cells in biology! But I noticed your question is worded a little differently so the nucleus would be the one thing a eukaryotic cell has that a prokatyotic cell does not...
The Hardy-Weinberg equation is as follows:


Where:
(convert all % to decimals)
p= homozygous dominant
q= homozygous recessive
pq= heterozygous
While you did not specify whether the 0.2 frequency was for dominant or recessive, we can still figure out the answer.
Using the 1st equation, we can solve for the other dominant/recessive frequency:
1-0.2=0.8
Meaning that:
p= 0.8 & q=0.2
If the heterozygouz frequency is 2pq, then it becomes a simple "plug & chug" sort of approach.
2(0.8)(0.2)= 2(0.16)= 0.32
So, the heterozygous frequency would be:
0.32
Hope this helps!