The answer is A, please mark brainliest.
A pair of lowercase letters represents a recessive gene.
For further clarification, if needed... If the punnett square was for dark hair being dominant over blonde hair, the offspring that was represented by two lowercase letters in a punnett square would have a phenotype of blonde hair.
Answer: 
This is the same as saying 
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Work Shown:

where 
As the steps show above, the idea is to factor the radicand into smaller pieces where one of those pieces is the largest perfect square possible. In this case, 36 is the largest factor of 180 that's a perfect square. Then I used the rule
to break up the root.
The parenthesis used at the very end is to help separate the
from the
term. The "i" is not under the square root.