Twin type has less to do with what twins look like and more to do with how they formed.
Identical, or monozygotic, twins form when a single fertilized egg splits and develop as two babies in the uterus. Identical twins originate from the same combination of cells and have the same genetic origin. They are ALWAYS the same sex, two girls/two boys. They may look very similar and it may be difficult to tell them apart.
Fraternal, or dizygotic, twins are two individuals from the same pregnancy who from TWO SEPARATE eggs fertilized by TWO SEPARATE SPERM. The genetic similarity between fraternal twins is the same as any two siblings, about 50 percent. They can be boys, girls, or one of each.
Answer:
The thickness is 
Explanation:
From the question we are told that
The wavelength is 
The first order of the dark fringe is 
The second order of dark fringe considered is 
Generally the condition for destructive interference is mathematically represented as

Here y is the path difference between the central maxima(i.e the origin) and any dark fringe
So the path difference between the 16th dark fringe and the 6th dark fringe is mathematically represented as

=> 
=> 
=> 
Yes it is, it was made in France as a gift to the U.S.A.